AI Bot PM replies stopped working on one multisite instance

,

We’re running a hosted, multisite Discourse setup with two instances (eg X and Y) on the same environment.

On the X instance, clicking the AI chat icon on the homepage creates a proper AI conversation (/discourse-ai/ai-bot/conversations/...) and the AI responds normally.

On the Y instance, clicking the same AI chat icon now creates a regular topic (/t/...) instead, and no AI model name or bot responses appear. This previously worked on Y and stopped recently.

We’ve verified that:

  • Both instances are on the same Discourse and discourse-ai versions

  • Persona configuration, allowed groups, and models match

  • Chat is enabled on both instances

In the database, we also see that new topics on Y are missing some AI-related topic custom fields that exist on the working instance (X).

We’re trying to understand what conditions control whether the AI chat creates a real AI conversation vs. a normal topic, and what could cause this behavior to regress on a single instance.

Has anyone seen similar behavior or have suggestions on what to check?

Thanks in advance.