Tweener in pan/crop go wrong when angle is more than 90° or -90°.
I create two keyframes which differ in angle. First keyrframe is -90°. Last keyframe is 0°. By rights tweener will create keyframes which only vary in angle.
before tweener :
However, the tweener create keyframes which vary in width and height.
after tweener:
Maybe @altarvic can have a look at it.