This is an ongoing, intermittent issue with Illustrator on Mac. It predates the M-series chips in my memory. The issue is that when the GPU preview is on the pasteboard starts to flicker (see attached). This is not tied to a specific action or effect in my experience, but happens randomly. Suggestions are to turn off GPU preview (not terribly helpful) or turn it off/on which sometimes works, or restart which sometimes works. Can you PLEASE figure out why this happens (has been happening for years!) and fix it.