Bet you we could figure it out pretty easily.

If I had to guess though, the answer is that you are dumping your hands at/before the ball. What is causing your hands to be dumping early though? Your hips may rotate but has your upper body completely stopped? There could be a number of reasons, but you could try using the thought of hitting the ball with the back of your left hand and holding that after impact to try and keep your wrist angle through the ball. You could be doing all the things you mentioned but still dumping/flipping your hands too soon. That would be the first thing I try given what you've said.

Your head may also be moving back while trying to get your weight forward and clearing your hips. That could cause it as well. You may also try keeping your head at or slightly ahead of the ball through the swing, though this may cause many golfers to slice the ball.