you're right, he's cork screwing... feet are buried in one spot and he starts his hands while the rest of his body is way behind. You can't hit if your legs are out of sync with your body.
question is why it's not getting better. Hitting coach has to see it and his swing is getting worse daily.... If anyone needs to spend some time in AAA Pillar is a candidate. the problem is that they don't have any outfielders. Carrera sucks balls and Bautista is hurt. there are no good options.