I am a Mac user, and was one of the ones that had this work as a fix previously. However, with the new patch, it has recurred and with some oddities. I’ve noticed that characters that were not part of season 21 do not have the issue unless they are wearing a fair bit of season 21 gear.
When this started again after the patch, I tried changing the video settings again to no avail. Following another suggestion in the Mac thread, I cleared the D3 Data folder and the entire PTR folder and freshly installed the game - again no effect.
Currently on MacBook Pro (retina, 13 inch, mid 2014)
Processor - 2.6 GHz dual core intel core i5
Graphics Intel Iris 1536 MB
Mac OS Catalina 10.15.5
Hope this gets figured out and glad Blizz looking into it.