I am by far nothing in the way of an expert or even professional, but…
I'd look at the running being the culprit, personally, esp running form
I mainly wonder if after working out some tightness/flexibility/mobility issues, if then the running with non-great form somehow is the issue. Like, her body finally starts chaining the way it's supposed to, and then she puts herself back into old movement patterns.
If she's been compensating for weak/tight/imbalanced/etc spots in her chain, fixing that is gonna reveal other issues as well.
I hope that thought was coherent.
