Wierd bone rotations

Hey guys, been having some problems with this specific model and its bone rotations. No other skeleton has this, i am wondering what could it be. I am using IK chain on torso-head linking, that for now stays only suspect but i cannot remove it, it would just be too rough to animate model otherwise. Not sure exactly what is the problem, but the lower jaw bone keeps rotation around its origin. In 3ds max all is fine.


3ds max skeleton: