I've never had my "jump to first unread post" jump strangely, but I've never been able to figure out why some forums (especially Farming) show unread posts in the ATP Home page, despite there being no recent unread posts as shown by the order of the threads in the forum.
Is there anything other than sticky threads that could influence the order of threads displayed in the Forum home page? I assumed that threads were listed by the date of the most recent post in that thread..
I can go into a forum, read several posts, exit by clicking on ATP Home, and see "no" in the Home page.
Then a little while later, it may show "yes" and I'll go back into the forum. I expect that if there was a new post, it would be more recent than any in the threads I just checked. So the thread with a new post "should" be at the top of the list (after any sticky threads). Yet the top several threads will all show "no".
(I haven't yet done any searches for threads not being listed in the order that I expected.)
For a while maybe that was because I used a back arrow instead of "ATP Home" to get out of the forum. But I don't do that any more. if it was a rare occurrence, I would assume that I had a brain freeze, but it happens multiple times per day, sometimes when I'm SURE I hit Home.
Then I thought it might be some race condition, and I was clicking around too fast for the electrons to keep up. Naah, I type fast but not THAT fast!
The best theory I've heard is that someone started to post to a thread, and then exited or their connection broke before they could hit "Finished". Maybe one mechanism used by the ATP Home Page detected a new post, but it "went away" before the forum could capture it.