I have a 2018 (3rd Gen) iPad Pro 12.9" that has been doing this for the past 6 months, and its driving me nuts. It happens in any app or on any screen. I tried a reset, and then I performed a clean install of iPadOS, neither worked. I contacted Apple last month, and they claimed they have never heard of this issue. They wanted to replace my iPad, but I wanted to wait for the new iPadOS. After the iPadOS 13 update, the issue persists, although it might happen less, I can't be 100% sure.
I think I might let Apple replace my iPad now, but I don't like doing that. I hate giving up an iPad that I know I treated well, with a refurb, the history of which I do not know.
Do you think this is software or hardware related?