Each time it's been a tiny rectangle of a handful of pixels at a random place on the screen that just turn some random color (bright purple the first time, bright green the second time). The first time was on Firefox and the second was on Apple Music, so it's not specific to the app. As soon as I scroll or otherwise cause the screen to update, they go away.
My guess is it's a GPU thing, not a screen thing. Has anyone else seen this? And do you think I should be worried? Could it represent a hardware defect in the GPU, or just a software problem (driver perhaps?) that could get patched out later if it becomes significant/widely-noticed?
Saw the same artifacts/glitches on my 2016 and 2018 15” models.
See them occasionally in Safari on my 16” now, usually up near the top window border.