WordPress/Internet Explorer Bug That Even Affects WPMU.org

NetPotion Elite
Gunning for gold!

Ok, so here's the deal.....

I stumbled across something that appears to be a WordPress bug, but I don't have a clue why it's happening -or how to fix it.

This bug DOES NOT appear in NetRenderer or Browsershots.org - but I have verified it happening on two local computers. I have a client who also sees this who is over a thousand miles away.

It's happening on a lot of WordPress sites, including WPMU.org.

If I view a bad link in IE on a WordPress site, I either get a completely broken page - or I get a jumbled mess of unformatted content.

Example: In IE9 - if I visit http://premium.wpmudev.org/blog/something.php I will get a broken page. Nothing shows up at all.
If I visit http://premium.wpmudev.org/blog/22 I get the result you see in the screenshot I've attached.

Now if I view the same pages in IE8 I get the same broken page with the first link, but I get a 404 with the second.

These same pages render fine in Chrome & Firefox! Grrr!

None of this appears when using online browser renderers which is baffling. I've cleared my cache and it makes no difference.

Does anyone have any ideas how to fix this issue?

This happens even if using a new setup with the default template - so I almost have to assume it's some kind of bug with WordPress. I've spent a huge amount of time on this & I really hope someone has a suggestion.

Besides, it's in the best interest of WPMU.org not to have folks seeing what I'm seeing. ; )

I appreciate any ideas you might have. Check your own sites in IE9 - odds are this is happening to you too. If you don't see it when you are logged out, try logging in and entering a bad url. I've noticed a difference when the cookie has been set - but only with some websites - and only in IE.

~ Corey