Unread posts link intermittently weirding out

[TuggyNE]

Recently, about 5-10% of the time when I click the Go to first new post image link next to a thread, it considers posts I've already seen to be unread, often as far back as the beginning of the current page. I don't believe I've seen this problem before about a week ago, and I'm unfortunately not sure how to reproduce it.

Anybody have insights, more reliable repros, or the like?

[Rockphed]

Is this related to posts not showing up properly? I.e. does this happen when the most recent post is either invisible without checking the reply function's review of the topic or does not match the most recent post according to the thread list?

If you know a couple of threads and when it happened the mods might be able to check if it is caused by problems with deleted or edited posts.

Did you make a post, go to the thread list, and then use the "go to first unread post" button to read the ninja replies?

Those are the only quirks of the forum software I have seen or, in the case of the second one, dream up. There are probably other issues possible.

[TuggyNE]

Is this related to posts not showing up properly? I.e. does this happen when the most recent post is either invisible without checking the reply function's review of the topic or does not match the most recent post according to the thread list?

If you know a couple of threads and when it happened the mods might be able to check if it is caused by problems with deleted or edited posts.

Did you make a post, go to the thread list, and then use the "go to first unread post" button to read the ninja replies?

Nope, probably not, and nope. The cases are generally where I've already seen those posts once before with "go to first unread post", and seem unconnected to paging problems.

Example: first two posts on the last page of D&D 5th Edition: Thread #7. I saw them with "go to first unread post", also opened the page link (I like to have all page links marked as visited in my browser, don't ask), and then several hours later opened first unread post again, and it took me to those and marked them unread.

Edit: another example is http://www.giantitp.com/forums/showt...2#post14216862 through http://www.giantitp.com/forums/showt...5#post14217195 were re-displayed.