I have noticed a recently developing event in Firefox. When scrolling through some pages such as LinkedIn or Facebook, my screen will suddenly go completely white. It seems to freeze for a second or two, then comes back. This has only been happening for about the past two or three weeks, so since about 1 April 2021 for time reference. My About Firefox shows I am running 87.0 (64-bit) and it is up to date. I completely uninstalled - including the deletion of the Mozilla folders per info on the web - then reinstalled. This did not correct the issue. I also run Chrome and do not experience this issue when using it.