Seemingly at random, a thread that I have already checked the latest posts on will sometimes still have the little blue marker showing it's unread on them. It seems to go away on its own after a while. It's only ever been one at a time. Most recently it's this thread, but it's also happened with this thread and this one, and possibly others I can't remember. It seems to only happen late at night or early in the morning and lasts until there's a new post in the thread.
It doesn't seem to have any other effect other than the marker not disappearing, and the position of the thread doesn't change on the "my bookmarks" page. Just weird, I thought.
What happens is it (sometimes) fixes itself when a new page is reached. Unless the new page gobbles up a post or two as well, then it continues for that page.
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