Goes on the last time you logged in ,if you don't actually log out it stays from that last time. Mine had until recently 8th August as last time i was on the forum ,Which is obviously BS.
Mine shows the same thing. It shows 1 unread PM when I do not see any new messages? Actually I just took a better look and I see that there is 1 unread message... but it has no title and was sent 6:00PM 12-31-1969!
Ummm... LPF didn't even exist then.