We have been covering the random issue with the AdSense login/logout issues for several months now. It appears some are now saying the issue is resolved.
A WebmasterWorld thread has several AdSense publishers claiming the logout bug is resolved. They said they no longer get automatically logged out after 10 minutes or so.
Yep, either they've fixed it at last or the autologout kicks in after a longer time - for me it seemed like every 5 minutes, not 30. Let's hope it's the former, that was annoying indeed!
Yeah, I've noticed it too. It used to toss you out after about 10-15 minutes. Now, it tosses you out after an hour or two. Not fixed, but much better.
Two hours of inactivity and logging you out, in my opinion is fine. Personally, I never really had this issue but many many publishers have.
Forum discussion at WebmasterWorld.