Even if I read all the posts from one machine, I still run across this.

Same here - single machine, I see many read->unread posts every day. It didn't used to be that bad.

More data: the number of new posts shown on the main index page is correct. Individual forums and thread views, though, show the extra unread posts.

Don't think it has anything to do with cookies. Tried clearing them, didn't help. There are only three cookies for empeg.comms.net anyway - username, password, and style.

Confuzeled,
Borislav