Hmmm, I had this issue in the early days (top spec MacBook Pro 16, 2.4Ghz 8-core, 2TB, 32TB, 5500M) and it's back again just now. Can't remember how I fixed it last time. So far it's visible in Google Chrome only. Been running some scientific calculations recently that caused the fans to work hard so I'm wondering if the heat has damaged something. Have been using the machine closed, with an external display connected. Guess it's time to call Apple support again. They were pretty good when my Touch Bar failed 6 months ago.
Update: As others suggested, deactivating hardware acceleration fixes the issue in Chrome. Guess I'll see if it rears it's head anywhere else...