Well, I just tried it a bit more meticulously on my own test phpbb3 board. Here's what I did, which did NOT result in the error:
- set posts per page to 10
- opened up IE and signed in one test user (U!), opened up FF and signed in another test user (U2)
- had U1 start a new topic and post 9 replies to it (10 posts total in the new topic)
- had U2 go to viewforum for the forum in question and click the yellow flag on that new topic so that U1 had read all 10 posts in that topic
- had U1 post another post in that topic so that the last post was now on page 2 of the topic
- had U2 go to viewforum for the forum in question and click the yellow flag on that new topic
Result...everything worked the way it was supposed to (U2 got brought to the first and only post on page 2 of the topic).
Although I would be surprised if this is the difference, the only thing I can think of at this point is that when I run into the trouble I have (I think) always clicked the yellow flag from search.php?search_id=egosearch
(rather than from viewforum). I note that when I click from there, the form of the address is slightly different. When I click from there, teh formof the unread post address is this:
rather than this:
Any chance the hilit= part could somehow mess things up? (Seems very unlikely but I thought I'd throw it out there.)
Handyman, do you use egosearch a lot the way I do to follow topics you have posted to? Would you only possibly only have run into the problem when using egosearch?