I have a similair issue.

I have the site's main page bookmarked but when I first get here I'm not logged into the site. I can tell because the background color is that ugly, baby-shit yellow. But as soon as I click on the forum link on the toolstrip menu at the top of the page, it changes to the dark background and I'm logged in.

It's not a huge deal but definitely something that didn't used to happen. IIRC it changed sometime last year.