The key difference, and the 'root' of the issue is her grip.
Note how well David has maintained his right wrist bend in the comparison above, vs. the flat right wrist position of Melanie.
Melanie's right hand grip is too much in her fingers, rather than being at the 'root', or base, of the fingers/palm. This forces her to take a stronger left hand grip in order to 'balance' the tendency of a right hand fingers grip to open the clubface, and doesn't allow her to keep her right hand wedge until follow through.
Both David's grip and Billy Herring's grip are far better, as you can clearly see in the impact and follow through positions in their sequences.
This is an area where TGM and 'traditional' teaching are rather different, and it is a VERY important difference.
Your pattern always comes back to your grip. I can certainly relate, as I had for many years used a right hand grip that was too far in the fingers - which just destroys the right forearm wedge.
Hitting chip shots right hand only can show you the proper location, at the 'root' of the fingers.
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