When I use the tool "Mark this forum read", all threads/posts initially are marked as read, as expected. But when I come back later, whether 15 minutes or hours, all the threads that were marked read have reverted to having new posts.
In a related problem, after I have read the last posts of some threads, the threads will show as read, but when I come back later, they are marked as having new posts, even though there have been no new posts since the last ones I read.
I don't have any special cookie setup with MiceChat, which is one place the problem could be. It could also be a database problem, where marking threads read is not being properly updated in the database.