Took my iPad Pro 512 back to apple last week
They don’t have a diagnostic tool to test the touch screen so they agreed to replace it it was 3 months old
Picked up a new one on Monday and restored from full backup on itunes
I was having the problem multiple times a day but since the replacement problem appears to have been resolved
One thing the genius guy suggested was to change the case as it was possible that the protective leather round the bezel could be shorting out the touch screen, obviously I had to take the case off and put it on the new unit so it’s possible I did a better job of keeping the protective cover off the touch screen. Anyhow worth trying to use your ipad without the case and see if this resolves the problem.
Personally I think that this was a hardware problem, it has become very clear Apples quality control has taken a significant dip in recent years so if you are in warranty and the change case fix doesn’t work push for a replacement.
One final point, when I checked in at the Genius Bar the guy gave me a look that I interpreted as ‘oh another one’ but when I questioned the engineer he claimed to have never heard of the problem. Call me paranoid but my feeling is that they know of this issue but want to minimise returns.
Good Luck