Since the behaviour is different based on the surface. (I seem to remember suggesting you clean your mouse mat before this in your original thread when you asked for recommendations actually) I'd still go and suggest again that you clean your mouse mat or just replace it.
By far the best mouse mat I have ever used is:
SteelSeries QcK Heavy Gaming Surface and is the one I am currently using with my own Corsair M95.
To clean it, I just take it in the shower and use "regular" shower gel and wipe it down with my hands, then leave it to dry flat on the airer.
Remember that the better the quality mouse you have the better quality mouse mat you require. Higher DPI also means that you need to use a smoother surface to avoid any unwanted "jumps"