Sometimes, I have to go to places real quick that I don't consider worthy to log out for, so I leave the page on Who's Online on every forum that I'm on, which refreshes every minute (10 minutes for this forum, I believe) so I stay showing as online.
I went somewhere 31 minutes ago (12:45 PM PDT), but when I got back and clicked my name, it showed my last activity being at 12:46 PM (PDT).
The point of Who's Online is that it keeps refreshing. A fix for this would be nice.
Please note that this isn't the first time that this has happened.