Thank you for the clarification Eric.RH was quoting me, but hasn't figured out how to use the quote feature
What I'm seeing is this hitter rotating her entire torso (hips, core, shoulders) as unit, rather than creating stretch/resistance through the core for her source of power. The rear leg over-rotating (heel flopping outward) seems to be a result of the torso rotation action. I see similar issues with my DD sometimes.
I believe what you perceive to see is being caused by an overcooking of the torso load in the direction orthogonal to what most folks believe hip rotation should take place in.