Turns collapse automatically while reading a finished session, timing unpredictable

[Raymond8196]

Problem

While reading a finished session, a turn can collapse by itself into the "Agent worked for …" bar without any user action. Content that is currently being read suddenly folds away, and the trigger timing is hard to predict.

Steps to reproduce

1. Open a finished session whose last turn has a fair amount of content.
2. Stay on the page and read without interacting.
3. After roughly a minute, the last turn collapses on its own while it is on screen.

Observed patterns (not fully confirmed, may help reproduction)

• It seems to only affect the last turn of a session; earlier turns are already collapsed when the session is opened.
• Sessions whose last turn is short do not seem to trigger it.
• Turns that were manually expanded sometimes fall back to collapsed after scrolling away and back, or after some time passes.
• After restarting the app, all manual expand/collapse state is lost.

Expected behavior

• Content the user is actively reading should not collapse automatically without any action.
• Manual expand/collapse state should persist reliably, and should not silently revert within the same session view.