Ok, tracked down the bug.
Basically, it was happening for those of you that access the site via http://siliconpopculture.com/sonytr. People who type or have http://www.siliconpopculture.com/sonytr bookmarked don’t see the problem.
I’m not sure what changed in between forum upgrades but perhaps some of the PHP code was acting different. I rewrote the detection routine to be a little more foolproof and you should always be redirected to the full URL with the WWW added on. This should also keep your cookies consistent as well.
Thanks for the input all. The problem should magically go away for you.