Editing non-last post causes thread to show 1 new post
Definitely not a critical one, but I don't see it posted here; first noticed it in the last day or two.
Fully read a thread in which you have a post which is not the most recent post [Edit: and not the OP!]
Edit that post
Bookmark list and forum index will show one new post.
Affects bookmarked, unbookmarked, and never bookmarked threads.
Triggered by first and all subsequent edits, edits do not stack.