Some strange animation glitches are happening while switching stances. While switching your stance from prone to the "last stand" (the one where you lay almost on your back) stance, if you do it at the right moments, gives some really weird animations. While holding a rifle and switching back and forth quickly, your legs will clip through the floor. This also moves you forward a very small amount. While holding a pistol and switching back and forth, your character flips out and, for a small period of time, your legs will be directly in the air. This happens every time I've tried it, with any character.