This issue still remains. My iphone 12 Pro have this issue since day one out of the box.

Hello Guys. I've been dealing with this issue on my iphone 12 Pro since I bought it 2 months ago and I found a simple solution that worked for me: Hard Reset. (Click volume up, click volume down and then click and hold power button for 10 seconds until apple logo show up) Before that I've tried Update the iOS, format the entire phone and nothing seemed to work. Then I've just hard reset yesterday and the stutter is gone! I've been using for almost 24 hours now and didn't experience any stutter whatsoever. I don't know if this solution would work for everybody, but definetly is worth a try.