Where there are a lot of unread topics, the count does not decrease when reading them.
The topic title and the unread message count bubble turns grey but does not go away and the unread topics count remains unchanged. Doing a page refresh updates everything.
Once the unread topics count gets down to a small amount it begins working normally again.
Windows 8.1 Pro, IE 11
P.S. New topics update fine when read. Trouble is only with the unread topics.