Was away, using phone to look at this forum, 2nd - 15th Aug and last night the forum was showing, correctly, the only unread discussion with new posts was the "endless thread".
This morning the new forum is showing all threads where the last post was after 2nd Aug had new messages, including threads looked at on this PC since 15th.
Not a major problem, but threw me when I logged-on this morning.
By the way the adverts on the phone version make it really difficult to follow threads. Don't get them on my PC version I assume because have an ad-blocker installed