Those are all helpful hints but I don't think that's what jimmy needs. He is already way to rear-side orientated. His pelvis is anteriorly tilted which is evidenced by his low knee lift, arched back, and posterior-side dominant running mechanics.
You don't need to stop the butt kick but don't try and make it happen. You shouldn't actually actively kick your butt with your heel (through knee flexion). Instead, the heel should come to the butt as a result of forcefully bringing up the thigh. Try to feel like you're stepping over the support leg with the swing leg.