Forum appears unread when no unread topics are present

This happened on area51.phpbb.com/phpBB

I recent marked all forums unread and all forum icons changed accordingly. This morning, after naderman posted http://area51.phpbb.com/phpBB/viewtopic.php?f=99&p=232357#p232357 I clicked into the topic and it was marked as unread on viewforum.php. However, when I go back to the main index, the forum (General Development Discussion) is still marked as unread. Also, clicking "View unread posts" yields no results.

According to bantu, there are some unapproved spam topics that might be causing this and this might possibly be fixed on the repository, but he asked me to report it just in case.