From weekly torch:
The reason is Cryengineâs way of interpolating feet between two animations. Instead of going from one pose into another, it sort of interpolates the first anim feet into a kind of default pose and then into the feet of the next anim. Our technical animators would be required for more in-depth explanation.
For me it´s much more disturbing the lack of footprints in the mud. And no mud on shoes and armor.