How to reproduce
- As a non autopatrolled B let a message on user A Flow talk page
- A hides the discussion
- A go to the talk page history, and ask the diff for the hidden revision
- A link "mark as patrolled" appears, it leads to ?title=Topic:...&action=markpatrolled&rcid=..
Expected behavior
The revision is marked as patrolled.
Actual behavior
a sessionfailure message