As I said above, mine goes away after driving a few miles, but when driven little or cold it does help when the rpm is up, so I just put it in nutreal, hold the brake, run it up to about 1000 then go to reverse real fast. and it gets smoother. Their seems to be a sweet spot. If I were you, I’d just do that when you back up until you figure it out. I have plenty of warranty left and I plan on trading it when the new 2022s comes out, so I’m not too worried about it, but if you plan on keeping yours a while, then I would definitely have the dealer fix it before warranty is up.
Also if they try to say it’s normal (like they did me), I would let them feel yours, then go get in another one on the lot that shifts smooth , so they can see the difference and that it’s not normal.