The rig doesn’t have any level of this distortion in Blender, as shown here:
However the left image was a pose, not in the animation like the other ones, but still, I’m not sure what could cause this level of distortion. I tried switching the legs and moving the bones around a bit, and moving the hip bone did help with the arm placement, now only the legs are distorted. The distortion only happens when looking at it during the animations which makes me think there’s issues with the bones being in wrong orientations.