Ya, videos don't lie do they?
I really don't see much movement to the left of the bow hand at release. I DO think you are "pushing" your bow shoulder out too much. (hyper extending) The bow shoulder should be relaxed, DOWN, and still -- not pushed out. I am not a fan of the "push/pull" system (NOT saying it's wrong, just that I am not a fan of it!) and I believe that that MIGHT be a cause of your feeling of instability there.
In the "push/pull" system, you are opening the bow with the bow hand and the string hand at the same time in a linear fashion, BUT that doesn't (or shouldn't) involve a forward push (movement) with the shoulder.
Also, note the bow hand catch you are doing. Fingers closing to catch the bow as you release. Relax those fingers to the back of the bow before you ever start to draw AND LEAVE THEM THERE. The bow will already be caught and with NO movement.
Regardless of how you draw, (rotational or push/pull) do not pull past your anchor references and then sink forward to anchor. That will disconnect you from your back and you end up with the string hand flipping out -- just like yours does.
Try to stand straight, then draw DIRECTLY to your anchor (don't have ANY string hand movement forward!!!!)and don't move your head to "go get the string." Your lack of follow through is simply loss of your back by the forward movement.
See if that helps any.
Arne