Take note of the first pause in the GIF below ... going into that pause you see the rear leg abducting & uncoiling ***AS*** the hands are drawn back into a strong punch-like orientation ... in a sense the drawing rearward of the hands is maintaining a coiling of the upper body, despite an uncoiling of the lower body.
Are you saying the rear hip is uncoiling?
The rear hip is constantly coiling. Look at the direction the rear hip starts as it coils. It doesn't change the direction. It continues in the direction of the coil and then goes through the inside of ball. Does that make sense?
Uncoiling would mean that it coils and then gives up the coil which would create slop.
JMO