I recorded a video of the bug happening. http://youtu.be/69VQab1k6R4
This video was taken on a brand new 5 button mouse with the dpi setting at 800dpi and mouse sensitivity turned down ingame as well. I have tried 2 other mice as well and all 3 do this. As I said this bug is repeatable in all my games. It doesn't happen at game menus or at the windows desktop.