I doubt that your problem has anything to do with the Lady's height, but sounds as though you have taken hold with her too far to your right side, and/or that you are using CBM so strongly on your forward step as to distort the track of the LF on or across the line of your RF (and so stepping in CBMP).
If you have Lady's thigh in your crotch, it may also be a fault in her backstep, in that she has not allowed her toe to slip back for the full extend of your stride (as indicated by your lead), but has shortened her own backstride by lowering to ball of foot early. This will have the effect of preventing any further backward movement, while you are still moving forward, with the inevitable coming together of the bits in between.
Of course, someone would need to see your movement to be certain.