He gave an example once, he said that he was on top near LG exit on t7, and fazz was down by RA. He went to turn the mouse right to hit fazz with the rail and he said that he went across his pad and it didn't go far enough. Given that he was using sens ~5, mouseaccel 0.48, he should have done a 360 and some change in that distance when he only needed to turn about 30 degrees and didn't make it.
Almost no information has surfaced about the bug. If rapha's experience was typical, given what he has said I would say that it's an issue with windows 7 + usb polling rate adjusters + QL's WM_INPUT mouse code. Unfortunately there is certain to be other players in the same situation, and reports similar to rapha's are almost unheard of.
His config was cleaned up, and I know he's tried new mouse + pad. Part of me suspects that it's all in his head. There just isn't enough information though.