I recently came across this issue on a 2nd gen iPad Pro. I had been having the problem most days, so I attempted to have it looked at the Apple Store. They couldn’t find anything wrong with it, but offered to happily replace it for the cost of a new device. Of course, at the store my iPad played very nicely and I couldn’t reproduce the problem.
Once I got home, I tried using the iPad and all was fine up until the point when I brought it back to my workstation. Then, it started acting up again. After several more trials, I noticed that it would act up more frequently in certain areas of the house but not in others. But the most common place was on my stand-up desk, where the power lines conveniently run directly underneath where my iPad usually sits.
I don’t have the tools to do a deep dive on this, but I believe the real issue may be electromagnetic interference of sorts. Could be improperly shielded cables or anything in-between. Seems like something worth investigating though.