Using Chrome, Windows XP:
Go to StackOverflow.com, click a question to view it, click back button to go back to StackOverflow.com.
My irrelevant questions are grayed out, but they are not removed.
UPDATE: I just reproduced it by clicking on my own question, voting for it (getting the message that said I couldn't), then clicking back.
FOUND IT: Close all your open tabs/windows of StackOverflow.com. Open a new tab, go to StackOverflow.com, click a question, click back, and there it is. It even does it when I am on StackOverflow.com, go back to my speed-dial page, click on StackOverflow, click question, click back.
It seems once you have been on the site a while, this no longer happens, but when you initially hit the site, this occurs (for me) 100% of the time.
