I can expand on this: it's not really just that the wrong icon is displayed: the wrong version of IE is being launched too (in my case, because I have ie9 installed and wangled in there, it's ie9, so I don't know what others will experience). I can tell from the context menu which pops up when right-clicking on the page.

Note though: this only happens when launching multiple versions at once with the quick button -- if I manualla select a v8 IE, i get a v8 ie with the correct icon.