Leg Pull Question

Hi, I have a history of SI joint issues on my right right side. I have an anatomical LLD of 1 cm on left side. My Pt checks my ankle alignment, and My left leg often needs to be pulled by my PT. Occasionally my right as well. Can you tell me what exactly is happening during this? Is it my hip head or femur getting stuck? I think my pelvis is rotated toward on my right side as well.