I basically have this problem right now. I have this monitor since Feb 2019 and this problem first occured around April 2020 (in just a bit more than 1 year), then went away in a few months. Now it started to appear once again about 2 weeks ago.
It doesn't effect me much, since it happens when I boot the monitor and goes away within a few minutes but of course you never know when it will decide not to go away.
Have you ever bumped into a problem like this? Is there a solution? I updated the firmware a few months ago but no change.