diff --git a/src/plugin_system/plugin_manager.py b/src/plugin_system/plugin_manager.py
index 22f8b470..9a2512df 100644
--- a/src/plugin_system/plugin_manager.py
+++ b/src/plugin_system/plugin_manager.py
@@ -12,6 +12,7 @@
 import subprocess
 import time
 import threading
+import types
 from pathlib import Path
 from typing import Dict, List, Optional, Any
 import logging
@@ -828,8 +829,18 @@ def run_scheduled_updates(self, current_time: Optional[float] = None) -> None:
                         # If resource monitor exists, wrap the call
                         def monitored_update():
                             self.resource_monitor.monitor_call(plugin_id, plugin_instance.update)
+                        # SimpleNamespace stores `update` as an *instance*
+                        # attribute, so attribute lookup returns the plain
+                        # function object as-is. A dynamically-built class
+                        # (`type(..., {'update': monitored_update})`) instead
+                        # stores it as a *class* attribute, which the
+                        # descriptor protocol turns into a bound method on
+                        # access -- silently prepending the instance as an
+                        # implicit first argument to a function that takes
+                        # none, raising "monitored_update() takes 0
+                        # positional arguments but 1 was given" on every call.
                         success = self.plugin_executor.execute_update(
-                            type('obj', (object,), {'update': monitored_update})(),
+                            types.SimpleNamespace(update=monitored_update),
                             plugin_id
                         )
                     else:
diff --git a/test/test_plugin_system.py b/test/test_plugin_system.py
index b78a3156..ae44d710 100644
--- a/test/test_plugin_system.py
+++ b/test/test_plugin_system.py
@@ -3,6 +3,7 @@
 from pathlib import Path
 from src.plugin_system.plugin_manager import PluginManager
 from src.plugin_system.plugin_state import PluginState
+from src.plugin_system.resource_monitor import PluginResourceMonitor
 
 class TestPluginManager:
     """Test PluginManager functionality."""
@@ -74,10 +75,58 @@ def test_load_plugin_missing_manifest(self, mock_config_manager, mock_display_ma
             
             # No manifest in pm.plugin_manifests
             result = pm.load_plugin("non_existent_plugin")
-            
+
             assert result is False
             assert pm.state_manager.get_state("non_existent_plugin") == PluginState.ERROR
 
+    def test_run_scheduled_updates_calls_update_with_resource_monitor(
+        self, mock_config_manager, mock_display_manager, mock_cache_manager
+    ):
+        """Regression test: run_scheduled_updates() must actually call a
+        plugin's update() when self.resource_monitor is set (as it is in
+        every real deployment -- display_controller.py and web_interface/
+        app.py both assign a real PluginResourceMonitor after construction).
+
+        Previously, the resource_monitor branch wrapped the call in a
+        function stored as a *class* attribute on a dynamically-built type
+        (`type('obj', (object,), {'update': monitored_update})()`), which
+        the descriptor protocol turns into a bound method on access --
+        silently passing the synthetic instance as an implicit first
+        argument to monitored_update(), which takes none. Every plugin's
+        scheduled update failed with "monitored_update() takes 0 positional
+        arguments but 1 was given" and was silently swallowed into a
+        circuit-breaker retry loop that never succeeded, so plugin data
+        (scores, odds, etc.) never refreshed.
+        """
+        with patch('src.plugin_system.plugin_manager.ensure_directory_permissions'):
+            pm = PluginManager(
+                plugins_dir="plugins",
+                config_manager=mock_config_manager,
+                display_manager=mock_display_manager,
+                cache_manager=mock_cache_manager
+            )
+
+            plugin_instance = MagicMock()
+            plugin_instance.enabled = True
+            plugin_instance.update = MagicMock()
+
+            pm.plugins["test_plugin"] = plugin_instance
+            pm.plugin_manifests["test_plugin"] = {"update_interval": 10}
+            pm.state_manager.set_state("test_plugin", PluginState.ENABLED)
+            # Plain MagicMock, not the mock_cache_manager fixture: this test
+            # is about run_scheduled_updates() actually invoking update()
+            # through the resource-monitor wrapper, not about
+            # PluginResourceMonitor's own cache-backed metrics persistence
+            # (which calls cache_manager.get(..., memory_ttl=...) --
+            # a kwarg the fixture's mock_get() doesn't accept).
+            pm.resource_monitor = PluginResourceMonitor(MagicMock())
+
+            pm.run_scheduled_updates(current_time=time.time())
+
+            plugin_instance.update.assert_called_once()
+            assert "test_plugin" in pm.plugin_last_update
+            assert pm.state_manager.get_state("test_plugin") == PluginState.ENABLED
+
 
 class TestPluginLoader:
     """Test PluginLoader functionality."""