Tried this with my 2017 iPad Pro 12.9" and I can see it happen on a dark background but I have to push with a fair amount of pressure to make it happen and it mostly seems to occur on the edges. I guess it causes the screen flex a bit closer to the backlight. With the Pencil I would have to press pretty hard to make it happen as well. In real use I have never noticed this.
If it occurs more easily on the new models then that's no good.