Do you always train this in the same location ?? Because it seems to me that she knows the direction where the treat is being tossed (behind her). If so, you need to throw the treat in all directions. Just thinking out loud ...
If this is not the case and you want her to make less mestakes. Click for lifting her fourth leg but not for putting it down yet. Reward her the second before the turn. And no more "out of hand treats" away from where you want her head to be. Now you are reinforcing the turn by feeding her there even though you click for her 4th paw in the box. I offen hear you clicking while the turning has allready started. Like at 2.58min, that's the position you need to feed her in in my opinion.
What I would also try is like you did at 1.38min Holding the treat in front of her so she is less motivated to turn.
I do love the calmness of your dog !! She is focused and yet no so ... border collie (if you know what I mean)

I remember the first box sessions with my dog ... They ripped the box into a 100 pieces
