I have the same issues. One thing I’ve read and props to brent brookbush for this. But he claims the TFL may have a big impact on hip internal rotation, especially in a 90/90 position. Theoretically the tfl causes a superior migration of the femoral head and stops proper internal rotation. Try releasing and then stretching the tfl into hip extension and external rotation and then retest your internal rotation. Works wonders for me! Goodluck all