Without video I am guessing she might be driving off the inside of her drive foot instead over “over her toes” and that has her hip alignment angled that way. Flat guessing though. Pitching with a powerline mat? Video would really help the gurus address the root of the issue better. I can think of maybe 3 things I would want to look at before saying “here’s why”.
I'm very interested in this line of thinking. My dd (also RHP) is having an issue dragging her toe. During her drive her right foot flips out to the right to some degree instead of pointing down and dragging. She has a strong drive and although it hasn't been a big issue yet, she could easily be called for illegal pitches when it is at it's worst. She has also had an issue stepping left at some points, though it isn't always in issue. Any thoughts about how to correct the issue if driving off of the inside of the foot is the problem?