When im playing, sometimes during a flick I notice like the movement goes on beyond the physical movement of my hand for a second. It's like for example I flick to the left, and the model continues turning to the left a bit after my hand stopped. It's weird to explain and happens randomly.

WTF is going on?

Im using it at 500hz with the MarkC Mousefix Builder
I dont know if this has been happening since I bought it or not. Its quite new.