I don't know if this is considered a bug, but in the bottom of threads where it displays "similar topics" it includes posts from Coalition Forums, which, of course, you can't see unless you're in the coalition. Edit: It also shows posts from the Moderator forum, which probably shouldnt be there. You can't actually view the post, but can see the titles still.
example:
http://afterwind.com/forum/topic.php?topic_id=1198
Ah yes, you can see an example at the bottom of this post too