You want to check that your back elbow is not getting trapped behind your back hip. That can force a flip. The Ross Move (and Ross Move Drill) can help. Make sure your arms have gotten back in front of the body as the body, rotating, drags the shaft through as you hold the shape. You may have to start with the front wrist bowed out a bit to help hold. The gap drill can help.
Also, make sure the ball is forward and your weight is 60-70% on your front side. Practice very short pitch shots (Fix Wrist Drill) keeping your wrists fixed on the backswing, and then all the way to the finish... then lengthen the shot until you find where you're starting to flip. Keeping the shaft in line with the front arm is not an easy thing. Most golfers have the urge to throw the club head to help... practice/warmup with the short pitch to show your body what you want to do. Become familiar with the correct move.
Move Less ... Get Good! DUPLESSISGOLF