My normal activity when logging in is to check subscribed threads, then new posts. Noticed recently that if I check the subscribed threads first, suddenly "new posts" shows 0. And when I click new posts, I get the "The threads below have not been updated since your last visit but still contain unread posts." message, but still can view the new posts. The posts still show as unread, but something is reporting to the new posts table that they have been read.