I've seen the below on the users page a few times in the last day. If I'm remembering correctly it was consistantly the top 3 or four users in the third column. It looks like the top 3 display over the next bottom 3. Although that is not consistant. I've also seen it where just one of the users was over another user several spaces down.
I was working on an XP box using IE8. I don't think I've seen it on my Win7 box, also running IE8 but I can't say that for sure. I do not see this every time but probably over half the times (maybe 4 or 5 times total).
This has now happened on my Win7 box with IE8 too.