Version 2.3.6
If you set Chat trigger for AI Agent to respond “Using response nodes”, the thinking dots do not display correctly after you’ve asked it something. If you set it to “When last node finishes” it works fine.
This makes for a pretty awful user experience because you can’t see that it’s actually doing something until it randomly outputs the response.
Hope this helps 
The issue you’re encountering with the AI Agent’s “thinking dots” not displaying correctly when using the “Using response nodes” trigger is a known bug in n8n version 2.3.6. It seems the visual feedback isn’t working as intended in that specific configuration. As you observed, the “When last node finishes” trigger does work correctly.
Unfortunately, there’s no immediate workaround within the current version beyond using the alternative trigger. You could consider upgrading to a newer n8n version, as the bug may be fixed in a later release.