MacBook Pro (16-inch, 2019) + ZMUIPNG dock same problem. Started happening after update to BigSur. I'm currently on 11.3, so based on previous comment likely I'll not get problem resolved on 11.3.1 :( This is my first ever MacBook, guess what is my impression right now

All it takes to run into this issue is turn monitor off then on, don't even need to disconnect any cables

@DelGurth mine has AMD Radeon Pro 5300M 4 GB yes