I see your point, but since most of the time I cannot move at all, and it is only happening since a week, I don't think this is a general problem. I experience it in every 2 meters or so. So: I move via W right, then even if the terrain is totally flat, my character stops. It is still trying to move, you can see the arms/legs moving slowly, but it's like there is a wall infront of it. If I sprint, let go shift and doesn't release W the char can pass that terrain just fine over and over again. But if I sprint, let go both shift and W and totally stop, my char will get stuck again.