Oooh wait, a new one! Every time I go to the site, it says I have 1 unread message, but it goes away when I open messages. This keeps me on the site long eno

Oooh wait, a new one! Every time I go to the site, it says I have 1 unread message, but it goes away when I open messages. This keeps me on the site long enough to look at my messages and click "mark all as unread" again.