I recently fixed a MacBook Pro Retina Mid 2012 (A1398) which had a bad screen flicker. The display would randomly glitch and produce artifacts in random locations on the screen. I haven't had any screen flickers or glitches since.
At first I believed it was the Vcore chip, U8900, but I had...
When using my MacBook Pro 2017 with the 560 GPU I see graphic glitches every day.
This happens especially while using zoom. I attached an example.
Another example while not using zoom