Ultrasurf 9.6+ filter

Here' s a good one. Users started complaining that certain web sites would no longer load start yesterday evening. I worked with one of my colleagues. Google Chrome and Firefox loaded the same sites without issue. Internet Explorer did not. I looked into application control and the web site was blocked due to the Ultrasurf 9.6+ filter getting hit (we block all proxy access, if possible). So now to get those few sites to load, I have to allow Ultrasurf 9.6+. This is stupid...