I haven't looked at the site, so I'm not sure, but my guess is this: When viewing a user profile, the page redirects you to another, so when you hit back, you go back to the redirect page, instead of the page you wanted to go to.

Solutions: In tear, either:

• Detect "redirect" pages, and remove these from the back history
• Allow the user to tap and hold the back button to pop up a back history selection dialog

Chrome implements the second point via right-clicking on the back button (they actually allow tap-and-hold, too). Firefox has the little arrow you can click on. Microb implements tap-and-hold.

Regardless, the best you can do for now is try to hit the back button twice, really quick. This is a change that needs to be made in tear, I'll file a bug.