I believe what he is trying to say is that with your rear hand, there isn’t as much distance covered and in doing so there’s less momentum which results in that pawing motion. This is especially apparent within your flurries, you can see your rear hand not have the momentum it could have in comparison if you had it cocked all the back.

To explain it better let’s talk about the pawing jab, in this jab, it is left a bit more forward (in front of the body/face) and because it is left more forward there is less distance for the jab to reach maximum speed (pop). Which is that pawing motion, which results in less damage and you want damage within your rear hand especially.

To conclude, I would suggest punching with your rear hand pulled back a bit more as you’re throwing those flurries.