We have many users and have noticed that screen share flickers on Chrome 83 in Windows on many machines. It almost seems like it is quickly switching between two different resolutions back and forth at the specified frame rate. The problem disappears when rolling back to Chrome 80 or when using Firefox (or when using Chrome 83 on a Mac). The problem seems to be happening on the receiving end, because viewing in Firefox shows no flicker for the exact same media stream. Also, the problem seems to be alleviated when the screen being shared is not maximized to full screen (or entire desktop), so it may be related to the resolution of the screen being shared.
At first I thought it was a problem with our config, but it reproduces consistently on https://meet.jit.si/ as well. Kind of surprised not to see any forum topics on this so far, as this problem is widespread among our users and is extremely distracting.