OP here. Ok, I may clear my cache as I haven't done that in awhile. It has happened several times now.

I looked through the logs and see one instance where you were looking at a thread and then went to the home page. I can't tell if you clicked on a link to go to the home page or go someplace else. The logs don't show any anomalies. I don't know what might cause this. Has it been happening for a long time? One thing you might do is clear your cache.

Some sort of glitch I'm sure but does anyone else ever have this happen? It's usually when clicking on a post in my firefox library box.