"Related contacts" field causes TypeError: this.localValue.trim is not a function

[Erkan-EdelKeramik]

Describe the bug

When I try to add the "Related contacts" field to a contact, the field does not work.

The browser console shows the following error:

TypeError: this.localValue.trim is not a function

Other additional contact fields, for example "Time zone", work correctly. The problem only occurs with "Related contacts".

I can reproduce the issue with different contacts.

Steps to reproduce

1. Open the Nextcloud Contacts app.
2. Open any contact.
3. Click "Add more information".
4. Select "Related contacts".
5. The field fails to load/work.
6. Open the browser console and the following error appears:
   TypeError: this.localValue.trim is not a function

Expected behavior

The "Related contacts" field should be added normally and allow me to select or link another existing contact.

Actual behavior

The "Related contacts" field cannot be used. When I add it, the Contacts app throws the following Vue error in the browser console:

TypeError: this.localValue.trim is not a function

No related contact can be selected.

Contact version

8.7.5

Operating system

Docker (official Nextcloud Docker image: nextcloud:34-apache)

PHP engine version

No response

Web server

Apache (supported)

Database

MariaDB

Additional info

Nextcloud version: 34.0.2
Contacts version: 8.7.5
PHP version: 8.5.8
Environment: Official Nextcloud Docker image (nextcloud:34-apache)
Browser: Firefox

Browser console error when adding "Related contacts":

TypeError: this.localValue.trim is not a function

Relevant stack trace:
addPropertyWithValue ical.js:8359
addProp ContactDetailsAddNewProp.vue:231
onClick ContactDetailsAddNewProp.vue:61

The issue is reproducible with different contacts. Other fields such as "Time zone" can be added normally.