Since the list renders fine standalone but breaks in the VA admin context, the issue is specifically with the embedded list component on that page. Here's how to approach it:
1. Reset the list layout for that view
Go to sys_ui_list.do and search for records where the table is sys_cb_topic (or the relevant setup topic table) and the View is tied to the Virtual Agent admin page. There may be a corrupted or incompatible list layout for that specific view. Try deleting that view-specific list layout so it falls back to the default — the platform will regenerate it.
2. Clear the declarative actions cache
Navigate to System Diagnostics > Cache Management and flush the cache (cache.do). Specifically, type cache.do in the navigator and click the "Flush" button. This forces the platform to rebuild the declarative actions metadata that's failing.
3. Check the sys_declarative_action_assignment table
Search sys_declarative_action_assignment for records tied to the setup topics table. Look for any records that reference missing or broken declarative action definitions. A broken or orphaned assignment record in this table is a common root cause for this exact error.
4. Try the classic UI as a workaround
If you're on the Next Experience (Polaris), switch to the classic UI by appending ?sysparm_view=classic or using glide.ui.polaris.experience to toggle. The embedded list rendering engine differs between the two, and this error is often Polaris/Next Experience-specific.
5. If none of the above works
As a practical workaround, manage your setup topics directly from the list (sys_cb_topic_list.do), filtering by the chat experience. You can add/remove/reorder topics from there. It's functionally equivalent — the VA admin page is just a convenience wrapper around those same records.
