diff --git a/app/views/common_templates/_search_results_template.html.erb b/app/views/common_templates/_search_results_template.html.erb
index deb9f250cf..e227c59355 100644
--- a/app/views/common_templates/_search_results_template.html.erb
+++ b/app/views/common_templates/_search_results_template.html.erb
@@ -387,9 +387,18 @@
   <% if full_name.to_s.start_with?('dynamic_model__') && option_type_config_name.to_s == default_option_type_name.to_s %>
   _fpa.state.caption_before.<%=name.underscore%> = _fpa.state.caption_before.<%=name_with_option_type.underscore%>;
   _fpa.state.labels_<%=name.underscore%> = _fpa.state.labels_<%=name_with_option_type.underscore%>;
-  _fpa.state.template_config.<%=resource_name%> = _fpa.state.template_config.<%=resource_name%> || _fpa.state.template_config.<%=name.underscore%>;
-  _fpa.state.template_config.<%=name.underscore.pluralize%> = _fpa.state.template_config.<%=name.underscore.pluralize%> || _fpa.state.template_config.<%=name.underscore%>;
-  _fpa.state.template_config.<%=name.underscore.sub('dynamic_model__', '')%> = _fpa.state.template_config.<%=name.underscore.sub('dynamic_model__', '')%> || _fpa.state.template_config.<%=name.underscore%>
+  <%# Alias the dynamic model's template config under its alternative resource
+      names (plural resource_name, pluralized name, and short name). The current
+      version's template object is aliased as before, but we must ALSO alias the
+      specific def_version key. Without this, when the base object already exists
+      from the initial page load (the current version), an older version's
+      template (loaded on demand via the template_config endpoint) is never linked
+      onto these alternative names, so versioned embedded items fail to render in
+      show mode (issue #1238). %>
+  <% [resource_name, name.underscore.pluralize, name.underscore.sub('dynamic_model__', '')].uniq.each do |alias_name| %>
+  _fpa.state.template_config.<%=alias_name%> = _fpa.state.template_config.<%=alias_name%> || _fpa.state.template_config.<%=name.underscore%>;
+  _fpa.state.template_config.<%=alias_name%>.v<%=def_version%> = _fpa.state.template_config.<%=alias_name%>.v<%=def_version%> || _fpa.state.template_config.<%=name.underscore%>.v<%=def_version%>;
+  <% end %>
   <% end %>
   
 <% end %>
diff --git a/app/views/dynamic_models/_search_results_template.html.erb b/app/views/dynamic_models/_search_results_template.html.erb
index 4c2524985e..a07f38da1a 100644
--- a/app/views/dynamic_models/_search_results_template.html.erb
+++ b/app/views/dynamic_models/_search_results_template.html.erb
@@ -2,4 +2,15 @@
   next unless m.implementation_class_defined?(::DynamicModel, fail_without_exception: true)
 %>
   <%= render partial: 'dynamic_models/search_results_template_item', locals: { def_record: m } %>
+  <%# Also emit JS-only template_config entries for older history versions so that embedded
+      items created before a definition version bump can still resolve their vN key (issue #1238).
+      The common _search_results_template already skips Handlebars HTML-template rendering
+      when def_version is non-nil, so this only produces the lightweight JS config block. %>
+  <% m.all_versions.each do |historical_version|
+       # Skip the latest history entry: it corresponds to the current live record, whose
+       # config is already emitted above with def_version=nil.
+       next if historical_version.def_version == m.all_versions.first&.def_version
+  %>
+    <%= render partial: 'dynamic_models/search_results_template_item', locals: { def_record: historical_version } %>
+  <% end %>
 <% end %>
diff --git a/spec/requests/activity_log/embedded_versioned_template_config_spec.rb b/spec/requests/activity_log/embedded_versioned_template_config_spec.rb
new file mode 100644
index 0000000000..797a920fcb
--- /dev/null
+++ b/spec/requests/activity_log/embedded_versioned_template_config_spec.rb
@@ -0,0 +1,278 @@
+# frozen_string_literal: true
+
+# Request specs for issue #1238 — activity log embedded dynamic models fail to
+# render in show (read-only) mode when the embedded dynamic model uses
+# "definition versioning: version at record creation".
+#
+# User-facing symptom: after saving an activity log embedded form, the
+# read-only (show) form does not appear, and the browser console logs:
+#   fpa_state_item: could not find template_config dynamic_model__... v123
+# Editing the activity correctly shows the edit form, but on save/cancel the
+# read-only form is missing.
+#
+# Root cause exercised here: the activity log `template_config` endpoint builds
+# the Handlebars template-config <script> blocks for the embedded dynamic model
+# (see app/views/common_templates/_search_results_template.html.erb). For a
+# dynamic model, that partial aliases the per-version template object under the
+# model's alternative resource names (the plural `resource_name`, the pluralized
+# name, and the short name). It aliased only the BASE object, not the specific
+# `.v<def_version>` key. When the base object already exists from the initial
+# page load (the current version), an older version's template — loaded on demand
+# via this endpoint — was never linked onto the plural resource name. The browser
+# data item looks up `template_config.<resource_name>.v<version>`, finds nothing,
+# and logs `could not find template_config dynamic_model__... v123`, so the
+# read-only (show) form never renders. Unversioned models always use the current
+# version, which is already loaded, so they were unaffected.
+#
+# These tests assert that the activity log template_config response aliases the
+# embedded dynamic model's per-version template onto its plural resource name,
+# for both a versioned and an unversioned embedded dynamic model, including when
+# the embedded record was created under an older definition version.
+
+require 'rails_helper'
+require './db/table_generators/dynamic_models_table'
+
+RSpec.describe 'ActivityLog embedded dynamic model template_config', type: :request do
+  include MasterSupport
+  include ModelSupport
+  include ActivityLogSupport
+  include PlayerContactSupport
+  include DynamicModelSupport
+
+  AlNameEmbedTplCfg = 'Embed Template Config 1238'
+
+  before(:all) do
+    @prev_allow_dms = Settings::AllowDynamicMigrations
+    change_setting('AllowDynamicMigrations', true)
+    @prev_disable_vdef = Settings::DisableVDef
+    # Ensure definition versioning is active so the versioned dynamic model
+    # genuinely relies on the on-demand template_config endpoint.
+    change_setting('DisableVDef', false)
+  end
+
+  after(:all) do
+    change_setting('AllowDynamicMigrations', @prev_allow_dms)
+    change_setting('DisableVDef', @prev_disable_vdef)
+  end
+
+  before(:each) do
+    @admin = create_admin.first
+    @user = create_user.first
+    @master = create_master(@user)
+
+    @al_table = 'activity_log_player_contact_test_embeds'
+    @al_fk = "#{@al_table.singularize}_id"
+
+    setup_embed_target_models
+    setup_activity_log_with_embed
+
+    setup_access :player_contacts, user: @user
+    @player_contact = @master.player_contacts.create!(
+      current_user: @user, data: '(516)262-1291', rec_type: 'phone', rank: 10
+    )
+  end
+
+  # Build the two embed-target dynamic models, both with the FK column required
+  # for a direct embed:
+  #   - test_embed_versioned_recs    — uses definition-at-record-creation
+  #                                    versioning (default; no use_current_version)
+  #   - test_embed_unversioned_recs  — uses current version via
+  #                                    _configurations.use_current_version: true
+  def setup_embed_target_models
+    %w[test_embed_versioned_recs test_embed_unversioned_recs].each do |tn|
+      unless Admin::MigrationGenerator.table_exists? tn
+        TableGenerators.dynamic_models_table(tn, :create_do, 'test1', 'test2', @al_fk)
+      end
+    end
+
+    DynamicModel.active
+                .where(table_name: %w[test_embed_versioned_recs test_embed_unversioned_recs])
+                .each { |dm| dm.disable!(@admin) }
+
+    # Remove any stale Ruby implementation class constants from a previous test's run.
+    # With use_transactional_fixtures the DB rolls back between tests but in-memory Ruby
+    # constants persist. If the old class is still defined, prevent_regenerate_model will
+    # return it and skip regeneration for the new DM record, leaving the new DM's
+    # definition_id disconnected from the class (issue manifests as def_version = nil).
+    %w[test_embed_versioned_recs test_embed_unversioned_recs].each do |tn|
+      class_name = tn.singularize.ns_camelize
+      [DynamicModel, Object].each do |ns|
+        ns.send(:remove_const, class_name) if ns.const_defined?(class_name, false)
+      rescue NameError
+        nil
+      end
+    end
+
+    DynamicModel.create!(current_admin: @admin, name: 'test embed versioned recs',
+                         table_name: 'test_embed_versioned_recs',
+                         schema_name: 'dynamic_test', category: :test)
+                .update_tracker_events
+
+    unversioned_opts = <<~YAML
+      _configurations:
+        use_current_version: true
+
+      default:
+        label: Unversioned embed
+    YAML
+    DynamicModel.create!(current_admin: @admin, name: 'test embed unversioned recs',
+                         table_name: 'test_embed_unversioned_recs',
+                         schema_name: 'dynamic_test', category: :test,
+                         options: unversioned_opts)
+                .update_tracker_events
+
+    let_user_create :dynamic_model__test_embed_versioned_recs
+    let_user_create :dynamic_model__test_embed_unversioned_recs
+  end
+
+  # Configure ActivityLog::PlayerContactTestEmbed with two extra_log_types, each
+  # directly embedding one of the dynamic models above.
+  def setup_activity_log_with_embed
+    SetupHelper.setup_al_gen_tests AlNameEmbedTplCfg, 'test_embed', 'player_contact'
+
+    al = ActivityLog.active.where(name: AlNameEmbedTplCfg).first
+    raise "Activity Log #{AlNameEmbedTplCfg} not set up" if al.nil?
+
+    al.extra_log_types = <<~END_DEF
+      test_activity_versioned:
+        label: Versioned activity
+        fields:
+          - select_call_direction
+          - select_who
+        embed: dynamic_model__test_embed_versioned_recs
+
+      test_activity_unversioned:
+        label: Unversioned activity
+        fields:
+          - select_call_direction
+          - select_who
+        embed: dynamic_model__test_embed_unversioned_recs
+    END_DEF
+
+    al.current_admin = @admin
+    al.save!
+
+    @activity_log = al
+    @implementation_class = al.implementation_class
+
+    setup_access :activity_log__player_contact_test_embeds, user: @user
+    al.option_configs.each do |c|
+      setup_access c.resource_name, resource_type: :activity_log_type, user: @user
+    end
+  end
+
+  # Create an activity log record for the given extra_log_type and populate its
+  # directly embedded dynamic model with values, mirroring the user saving the
+  # embedded form.
+  def create_activity_with_embed(extra_log_type)
+    al = @player_contact.activity_log__player_contact_test_embeds.build(
+      select_call_direction: 'to player',
+      select_who: 'user',
+      extra_log_type:
+    )
+    al.master = @master
+    al.current_user = @user
+    al.save!
+
+    embed = al.create_embedded_item({ test1: 'embedded one', test2: 'embedded two' })
+    expect(embed).not_to be_nil
+    expect(embed.id).not_to be_nil
+
+    al.reload
+    al
+  end
+
+  def login_user(user = nil)
+    user ||= @user
+    sign_out :user
+    user.confirmed_at ||= Time.now
+    user.current_admin ||= @admin
+    user.save
+    get '/users/sign_in'
+    expect(response.status).to eq 200
+    sign_in user
+  end
+
+  def template_config_path(al)
+    "/masters/#{@master.id}/#{@implementation_class.definition.base_route_segments}/#{al.id}/template_config"
+  end
+
+  before(:each) do
+    login_user
+  end
+
+  # The plural resource_name is the key the browser data item uses to look up its
+  # template_config (e.g. `template_config.dynamic_model__test_embed_versioned_recs`).
+  # The per-version template MUST be aliased onto that name keyed by the record's
+  # def_version, otherwise show mode fails for that version (issue #1238).
+  def embedded_def_version(al)
+    al = @implementation_class.find(al.id)
+    al.current_user = @user
+    al.embedded_item&.def_version
+  end
+
+  describe 'versioned embedded dynamic model' do
+    it 'includes the embedded model template config in the template_config response' do
+      al = create_activity_with_embed('test_activity_versioned')
+
+      get template_config_path(al)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include('template_config.dynamic_model__test_embed_versioned_recs')
+    end
+
+    context 'when the embedded record was created under an older definition version' do
+      it 'aliases the record\'s older version of the embedded template onto the plural resource name' do
+        al = create_activity_with_embed('test_activity_versioned')
+
+        # Create newer definition versions of the embedded dynamic model until the
+        # record above resolves to a concrete, older (non-current) definition
+        # version. This is the scenario that triggers issue #1238: the record's
+        # template must be fetched on demand for that older version. Dynamic
+        # migrations are disabled during each bump to avoid a table-comment
+        # migration competing for a lock with the just-created record; version
+        # history is recorded independently of migrations.
+        record_version = nil
+        5.times do
+          sleep 2
+          dm = DynamicModel.active.find_by(table_name: 'test_embed_versioned_recs')
+          change_setting('AllowDynamicMigrations', false)
+          dm.current_admin = @admin
+          dm.options = "default:\n  label: Versioned embed v#{SecureRandom.hex(2)}\n"
+          dm.save!
+          change_setting('AllowDynamicMigrations', true)
+          DynamicModel.define_models
+          Application.refresh_dynamic_defs
+
+          record_version = embedded_def_version(al)
+          break if record_version.present?
+        end
+
+        expect(record_version)
+          .to be_present, 'expected the embedded record to resolve to a concrete older definition version'
+
+        get template_config_path(al)
+        expect(response).to have_http_status(:ok)
+
+        # The per-version template for the record's older version must be aliased
+        # onto the plural resource_name the browser data item looks up. Without the
+        # fix only the base object is aliased, so this version key is missing and
+        # the show-mode form fails to render (issue #1238).
+        expect(response.body)
+          .to match(/template_config\.dynamic_model__test_embed_versioned_recs\.v#{record_version}\s*=/),
+              "expected plural resource alias for version v#{record_version} to be present"
+      end
+    end
+  end
+
+  describe 'unversioned embedded dynamic model' do
+    it 'includes the embedded model template config in the template_config response' do
+      al = create_activity_with_embed('test_activity_unversioned')
+
+      get template_config_path(al)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include('template_config.dynamic_model__test_embed_unversioned_recs')
+    end
+  end
+end
diff --git a/spec/system/activity_log/embedded_versioned_show_mode_spec.rb b/spec/system/activity_log/embedded_versioned_show_mode_spec.rb
new file mode 100644
index 0000000000..efe6321c47
--- /dev/null
+++ b/spec/system/activity_log/embedded_versioned_show_mode_spec.rb
@@ -0,0 +1,455 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require './db/table_generators/dynamic_models_table'
+
+# System (acceptance) tests for issue #1238 — activity log embedded dynamic
+# models fail to render in show (read-only) mode after save when the embedded
+# dynamic model uses "definition versioning: version at record creation".
+#
+# Purpose / acceptance criteria (verbatim from the issue):
+#   "Acceptance tests must show that embedded dynamic models for versioned and
+#    unversioned work correctly and view in edit and show modes."
+#   "To avoid regressions, we must also test an activity log activity that has a
+#    `references` config with a single entry, so that the item appears embedded,
+#    even though it is referenced through model references."
+#
+# Strategy: AL records and their embedded / referenced DM records are created
+# programmatically (in the test thread, visible to the browser via Rails 7
+# transactional system tests). The browser then navigates to the master page
+# and we verify that the Handlebars client-side templates correctly render
+# the embedded DM in show (read-only) mode.  The KEY regression from issue
+# #1238 is that the plural resource-name alias in template_config was missing
+# the per-version key (e.g. `.v254`), so versioned-DM records at any version
+# other than the latest showed nothing.  After the fix the alias is set for
+# every version, so old records still render.
+#
+# Follows the pattern of spec/system/page_layout/initial_show_tab_spec.rb:
+# user + master created once in before(:all), login per example, page layout
+# created explicitly so the AL panel auto-expands via initial_show.
+describe 'Activity log embedded versioned dynamic model show mode (issue 1238)',
+         js: true, driver: $browser_driver do
+  include FeatureSupport
+  include MasterSupport
+  include ModelSupport
+  include PlayerContactSupport
+  include DynamicModelSupport
+
+  AlNameEmbedShow = 'Embed Show 1238'
+  AlProcessEmbedShow = 'embed_show'
+  AlFkEmbedShow = 'activity_log_player_contact_embed_show_id'
+
+  def setup_embed_target_models
+    al_fk = AlFkEmbedShow
+    # Drop and recreate each table to ensure the FK column matches the current
+    # AL table name.  (If a previous test run used a different AL process name
+    # the table may have an incorrect FK column.)
+    %w[show1238_embed_versioned_recs show1238_embed_unversioned_recs].each do |tn|
+      TableGenerators.dynamic_models_table(tn, :drop_do)
+      TableGenerators.dynamic_models_table(tn, :create_do, 'test1', 'test2', al_fk)
+    end
+    TableGenerators.dynamic_models_table('show1238_ref_single_recs', :drop_do)
+    TableGenerators.dynamic_models_table('show1238_ref_single_recs', :create_do, 'test1', 'test2')
+
+    DynamicModel.active
+                .where(table_name: %w[show1238_embed_versioned_recs show1238_embed_unversioned_recs
+                                      show1238_ref_single_recs])
+                .each { |dm| dm.disable!(@admin) }
+
+    DynamicModel.create!(current_admin: @admin, name: 'show1238 embed versioned recs',
+                         table_name: 'show1238_embed_versioned_recs',
+                         schema_name: 'dynamic_test', category: :test,
+                         options: "default:\n  label: Embed1238V\n  labels:\n    test1: LabelField1V1234\n")
+                .update_tracker_events
+
+    DynamicModel.create!(current_admin: @admin, name: 'show1238 embed unversioned recs',
+                         table_name: 'show1238_embed_unversioned_recs',
+                         schema_name: 'dynamic_test', category: :test,
+                         options: "_configurations:\n  use_current_version: true\ndefault:\n  label: Embed1238U\n  labels:\n    test1: LabelField1U1234\n")
+                .update_tracker_events
+
+    DynamicModel.create!(current_admin: @admin, name: 'show1238 ref single recs',
+                         table_name: 'show1238_ref_single_recs',
+                         schema_name: 'dynamic_test', category: :test,
+                         options: "default:\n  label: Embed1238R\n")
+                .update_tracker_events
+  end
+
+  def setup_activity_log
+    SetupHelper.setup_al_gen_tests AlNameEmbedShow, AlProcessEmbedShow, 'player_contact'
+
+    al = ActivityLog.active.where(name: AlNameEmbedShow).first
+    raise "Activity Log #{AlNameEmbedShow} not set up" if al.nil?
+
+    al.extra_log_types = <<~END_DEF
+      versioned_activity:
+        label: Versioned activity
+        fields:
+          - select_call_direction
+          - select_who
+        embed: dynamic_model__show1238_embed_versioned_recs
+
+      unversioned_activity:
+        label: Unversioned activity
+        fields:
+          - select_call_direction
+          - select_who
+        embed: dynamic_model__show1238_embed_unversioned_recs
+
+      ref_single_activity:
+        label: Ref single activity
+        fields:
+          - select_call_direction
+          - select_who
+        references:
+          - dynamic_model__show1238_ref_single_recs:
+              label: Referenced single
+              from: this
+              add: one_to_this
+    END_DEF
+
+    al.current_admin = @admin
+    al.save!
+
+    @activity_log = al
+    @implementation_class = al.implementation_class
+  end
+
+  def setup_access_for_user
+    setup_access :player_contacts, user: @user
+    setup_access :player_infos, user: @user
+    setup_access :activity_log__player_contact_embed_shows, user: @user
+    @activity_log.option_configs.each do |c|
+      setup_access c.resource_name, resource_type: :activity_log_type, user: @user
+    end
+    %i[dynamic_model__show1238_embed_versioned_recs
+       dynamic_model__show1238_embed_unversioned_recs
+       dynamic_model__show1238_ref_single_recs].each do |rn|
+      setup_access rn, user: @user
+    end
+  end
+
+  before :all do
+    # AllowDynamicMigrations and TwoFactorAuthDisabledForUser are set globally
+    # by config.before(:all, type: :system) in rails_helper.rb.
+    @prev_disable_vdef = Settings::DisableVDef
+    change_setting('DisableVDef', false)
+
+    SetupHelper.feature_setup
+
+    @admin = create_admin.first
+    create_user(create_master: false)
+    @app_type = @user.app_type
+
+    setup_embed_target_models
+    setup_activity_log
+    setup_access_for_user
+
+    # Page layout: auto-expand our AL panel so each test sees it immediately
+    # after navigating to the master record (initial_show: true).
+    @al_page_layout = Admin::PageLayout.create!(
+      layout_name: 'master',
+      panel_name: 'show-embeds-1238',
+      panel_label: 'Show Embeds 1238',
+      panel_position: 99,
+      app_type: @app_type,
+      current_admin: @admin,
+      options: "contains:\n  resources:\n" \
+               "    - activity_log__player_contact_embed_shows\n" \
+               "view_options:\n  initial_show: true\n"
+    )
+
+    @master = Master.create!(current_user: @user)
+    @master.current_user = @user
+    @master.player_infos.create!(first_name: 'Embed1238', last_name: 'Test', source: 'nflpa')
+    @player_contact = @master.player_contacts.create!(
+      current_user: @user, data: '(516)262-1291', rec_type: 'phone', rank: 10
+    )
+
+    DynamicModel.define_models
+    ActivityLog.define_models
+    DynamicModel.routes_reload
+    Rails.application.routes_reloader.reload!
+  end
+
+  after :all do
+    change_setting('DisableVDef', @prev_disable_vdef)
+    if @al_page_layout
+      # History records reference the layout via FK — must be deleted first.
+      ActiveRecord::Base.connection.execute(
+        "DELETE FROM page_layout_history WHERE page_layout_id = #{@al_page_layout.id}"
+      )
+      @al_page_layout.destroy
+    end
+  end
+
+  before :each do
+    # Clear precompiled Handlebars templates so the page layout created in
+    # before(:all) is included in the compiled master template for each example.
+    # (Pattern from spec/system/page_layout/initial_show_tab_spec.rb)
+    Admin::AppConfiguration.clear_memo!
+    HandlebarsPrecompiler.cleanup_tmp_dir
+    HandlebarsPrecompiler.cleanup_public_dir
+    Rails.cache.delete('server_cache_version')
+    login
+    # Each example creates its own records before calling navigate_to_master,
+    # so that the browser sees fresh data when the page loads.
+  end
+
+  # ===================================================================
+  # Programmatic record-creation helpers
+  # (Records are created in the test thread; they are visible to the browser
+  #  via the shared database transaction in Rails 7 system tests.)
+  # ===================================================================
+
+  # Create an AL record for @player_contact / @master.
+  def create_al_record(extra_log_type:)
+    @implementation_class.create!(
+      extra_log_type: extra_log_type,
+      select_call_direction: 'to player',
+      select_who: 'user',
+      player_contact: @player_contact,
+      master: @master,
+      current_user: @user
+    )
+  end
+
+  # Return the active implementation class for the given DM table name.
+  def dm_class_for(table_name)
+    DynamicModel.active.find_by(table_name: table_name).implementation_class
+  end
+
+  # Populate test1 on the auto-created embedded DM record (linked via FK) so
+  # that a concrete field value is visible in the rendered page.  The embed:
+  # config renders DM fields inline (seamless mode) without a label heading,
+  # so we assert on field VALUES rather than the DM label.
+  def set_embedded_dm_field(table_name, al_record, value)
+    dm_class = dm_class_for(table_name)
+    dm_rec = dm_class.find_by(AlFkEmbedShow => al_record.id)
+    raise "No auto-created DM found for AL #{al_record.id} in #{table_name}" unless dm_rec
+
+    dm_rec.current_user = @user
+    dm_rec.test1 = value
+    dm_rec.save!
+  end
+
+  # ===================================================================
+  # NOTE: for embed: config, the system auto-creates an embedded DM record
+  # via the link_embedded_item after_create callback when an AL is saved.
+  # Do NOT create DM records separately — that would create duplicates.
+  # ===================================================================
+
+  # ===================================================================
+  # Browser navigation helpers
+  # ===================================================================
+
+  # Navigate to the master page and expand the AL panel tab.
+  def navigate_and_expand_al_panel
+    navigate_to_master(@master.id)
+    expand_master_record_tab('activity_log__player_contact_embed_shows')
+    # Explicitly wait for the master search-results templates to compile.
+    # finish_page_loading exits early when body.sessions is present, so we must
+    # wait here to ensure Handlebars has the template_config and labels state
+    # before any label-specific assertions run.
+    page.has_css?('body.status-compiled', wait: 60)
+  end
+
+  # Clear Handlebars caches and re-navigate (needed after definition bumps).
+  def clear_caches_and_navigate
+    Admin::AppConfiguration.clear_memo!
+    HandlebarsPrecompiler.cleanup_tmp_dir
+    HandlebarsPrecompiler.cleanup_public_dir
+    Rails.cache.delete('server_cache_version')
+    navigate_and_expand_al_panel
+  end
+
+  # Bump the definition version of the given DM table by saving new options with
+  # the supplied label.  Disables dynamic migrations during the save so that the
+  # table-comment migration doesn't race with the just-created record; version
+  # history is tracked independently of migrations.  After saving it reloads
+  # model definitions and restarts the server so the new version is live.
+  def bump_dm_version(table_name, new_label)
+    sleep 2 # ensure a distinct created_at timestamp for the new version
+    dm = DynamicModel.active.find_by(table_name: table_name)
+    change_setting('AllowDynamicMigrations', false)
+    dm.current_admin = @admin
+    dm.options = "default:\n  label: #{new_label}\n  labels:\n    test1: #{new_label} Field\n"
+    dm.save!
+    change_setting('AllowDynamicMigrations', true)
+    DynamicModel.define_models
+    Application.refresh_dynamic_defs
+    AppControl.restart_server
+  end
+
+  # ===================================================================
+  # Shared examples
+  # ===================================================================
+
+  # Verifies that multiple AL instances each automatically show their own
+  # embedded DM block in show (read-only) mode.  Creating the AL record is
+  # sufficient — the link_embedded_item after_create callback auto-creates
+  # one DM record per AL via the FK column.  The `embed:` config then renders
+  # that DM form inside the AL show block.
+  #
+  # `dm_table` is the DM table name (e.g. 'show1238_embed_versioned_recs').
+  # The embed: config renders DM fields in seamless mode (inline, no label
+  # heading), so we populate test1 on each auto-created DM and assert on
+  # the titleized field VALUE appearing in the page.  If the template_config
+  # alias is missing (the issue-1238 bug) the entire block is absent and the
+  # field values never appear.
+  # `dm_label` is the version-specific label for the test1 field (from the DM
+  # options `labels:` config).  Its presence proves the correct per-version
+  # template is being used to render the embedded DM block.
+  shared_examples 'an embedded activity viewable in show mode' do |extra_log_type, dm_table, dm_label|
+    it 'shows embedded DM blocks in read-only mode and exposes edit buttons for each AL instance' do
+      # Two AL instances of the same type — the system auto-creates one
+      # embedded DM per AL via the link_embedded_item after_create callback.
+      al1 = create_al_record(extra_log_type: extra_log_type)
+      set_embedded_dm_field(dm_table, al1, 'embed item alpha')
+      al2 = create_al_record(extra_log_type: extra_log_type)
+      set_embedded_dm_field(dm_table, al2, 'embed item beta')
+
+      navigate_and_expand_al_panel
+
+      # Version-specific field label confirms the correct per-version template
+      # is rendered.  (Before the fix the block was entirely absent for
+      # versioned DMs; neither the label nor the value would appear.)
+      expect(page).to have_text(dm_label, wait: 20)
+      # Both field values must also appear — proves each AL instance's embedded
+      # DM block is rendered.
+      expect(page).to have_text('Embed Item Alpha')
+      expect(page).to have_text('Embed Item Beta')
+
+      # Each AL instance has its own edit button.
+      expect(page).to have_css('.edit-entity', minimum: 2, wait: 10)
+    end
+  end
+
+  # ===================================================================
+  # Versioned embedded dynamic model
+  # ===================================================================
+
+  describe 'versioned embedded dynamic model' do
+    include_examples 'an embedded activity viewable in show mode',
+                     :versioned_activity, 'show1238_embed_versioned_recs', 'LabelField1V1234'
+
+    # KEY regression test for issue #1238: after the DM definition version is
+    # bumped, a previously saved record is now on an OLDER version.  Without the
+    # fix in _search_results_template.html.erb the browser JS logs:
+    #   "could not find template_config dynamic_model__..._recs v<n>"
+    # and the show-mode form never renders.  With the fix the per-version alias
+    # is set on the plural resource-name key, so old records still display.
+    it 'still renders the older-version embedded item in show mode after a definition version bump' do
+      # Two AL instances at version N — auto-created embedded DMs via after_create.
+      # Populate test1 so we can assert on field values in the page.
+      al1 = create_al_record(extra_log_type: :versioned_activity)
+      set_embedded_dm_field('show1238_embed_versioned_recs', al1, 'pre bump alpha')
+      al2 = create_al_record(extra_log_type: :versioned_activity)
+      set_embedded_dm_field('show1238_embed_versioned_recs', al2, 'pre bump beta')
+
+      # First navigation: both AL instances show their embedded DM at version N.
+      navigate_and_expand_al_panel
+      # Version-specific field label confirms the initial version template is rendered.
+      expect(page).to have_text('LabelField1V1234', wait: 60)
+      expect(page).to have_text('Pre Bump Alpha')
+      expect(page).to have_css('.edit-entity', minimum: 2, wait: 10)
+
+      # Bump definition version (uses the bump_dm_version helper).
+      bump_dm_version('show1238_embed_versioned_recs', "Versioned v#{SecureRandom.hex(2)}")
+
+      # Re-navigate with fresh template_config (now at version N+1).
+      # With the fix the plural alias also carries the v<N> key, so both
+      # older-version AL instances must still render their embedded DM —
+      # confirmed by the original field label and values still appearing.
+      clear_caches_and_navigate
+      # Old version-specific label must still appear — proves the pre-bump template
+      # is still reachable via the plural alias after the version bump.
+      expect(page).to have_text('LabelField1V1234', wait: 20)
+      expect(page).to have_text('Pre Bump Alpha')
+      expect(page).to have_text('Pre Bump Beta')
+      expect(page).to have_css('.edit-entity', minimum: 2, wait: 10)
+    end
+
+    # Strongest regression test for issue #1238: two AL records on the SAME
+    # master page, each with an embedded DM saved at a DIFFERENT definition
+    # version.  Both must render their embedded DM content.
+    #
+    # Without the fix only the current-version alias exists in template_config,
+    # so the older record's embed block is silently absent — its field values
+    # never appear.  With the fix both version keys exist on the plural alias,
+    # so both blocks render and both field values are visible.
+    it 'shows each embedded item with its own version-specific content when two versions coexist on the same page' do
+      # Step 1: Create AL record 1 at the current version.
+      # The link_embedded_item after_create callback auto-creates the embedded DM.
+      # Populate test1 with a unique value to assert rendering at this version.
+      al_v1 = create_al_record(extra_log_type: :versioned_activity)
+      set_embedded_dm_field('show1238_embed_versioned_recs', al_v1, 'version one data')
+
+      # Step 2: Bump the DM definition to a new version.
+      bump_dm_version('show1238_embed_versioned_recs', 'Embed1238-Two')
+
+      # Step 3: Create AL record 2 at the new version.
+      # Auto-created embedded DM now uses the new definition version.
+      al_v2 = create_al_record(extra_log_type: :versioned_activity)
+      set_embedded_dm_field('show1238_embed_versioned_recs', al_v2, 'version two data')
+
+      # Step 4: Navigate fresh so the browser loads template_config for both versions.
+      clear_caches_and_navigate
+
+      # Both embeds must appear with their own field labels and values visible.
+      # al_v1 resolves to version N   → label 'LabelField1V1234', value 'Version One Data'
+      #                                  (requires the plural-alias fix)
+      # al_v2 resolves to version N+1 → label 'Embed1238-Two Field', value 'Version Two Data'
+      expect(page).to have_text('LabelField1V1234', wait: 20)
+      expect(page).to have_text('Version One Data')
+      expect(page).to have_text('Embed1238-Two Field')
+      expect(page).to have_text('Version Two Data')
+    end
+  end
+
+  # ===================================================================
+  # Unversioned embedded dynamic model
+  # ===================================================================
+
+  describe 'unversioned embedded dynamic model' do
+    include_examples 'an embedded activity viewable in show mode',
+                     :unversioned_activity, 'show1238_embed_unversioned_recs', 'LabelField1U1234'
+  end
+
+  # ===================================================================
+  # Single-entry references: referenced item appears embedded in show view
+  # ===================================================================
+
+  describe 'single-entry references config' do
+    it 'shows the referenced DM item embedded in the activity show view for each AL instance' do
+      # Two AL instances each with a single referenced DM (mirrors "add: one_to_this").
+      # The references: config causes the linked DM to appear automatically embedded
+      # within each AL show block.
+      al1 = create_al_record(extra_log_type: :ref_single_activity)
+      ref_dm1 = dm_class_for('show1238_ref_single_recs').create!(
+        test1: 'ref item alpha',
+        test2: 'ref data alpha',
+        master: @master,
+        current_user: @user
+      )
+      ModelReference.create_with(al1, ref_dm1)
+
+      al2 = create_al_record(extra_log_type: :ref_single_activity)
+      ref_dm2 = dm_class_for('show1238_ref_single_recs').create!(
+        test1: 'ref item beta',
+        test2: 'ref data beta',
+        master: @master,
+        current_user: @user
+      )
+      ModelReference.create_with(al2, ref_dm2)
+
+      navigate_and_expand_al_panel
+
+      # Both referenced DM items must be visible — fields render as
+      # "field_name Titleized Value" pairs inline in the AL panel.
+      expect(page).to have_text('Ref Item Alpha', wait: 20)
+      expect(page).to have_text('Ref Item Beta')
+      expect(page).to have_css('.edit-entity', minimum: 2, wait: 10)
+    end
+  end
+end