I tested it using IE10 on a Windows 8 virtual machine, and also tried it on my Win 7 dev machine with the IE10 preview. Both failed in the same way.
I looked at the web traffic on the client side using Fiddler. (What a great program! But I just noticed, via a message that appears in the upgraded Fiddler, that they have “joined the Telerik family”. Interesting. They say they’re going to keep it free… fingers crossed that remains true!)
Anyway I tried hitting the test site with IE10, and then I tried it with Chrome on Windows 8; then I also tried IE 8, running on my Win 7 dev machine. Here’s what I saw when I looked at the “Raw” view for the 302 redirect event. The problematic string is shown in red. It seemed to be stuffing some long encrypted string in front of the redirect URL.
IE8 on Windows 7: