Good thought. I have had this problem daily for 2 weeks now. Today (3/23) when I rewoke the computer, which is what I always do as I never power off or log off, I immediately got the dialog box which I closed. However, for the first time the taskbar worked fine on both monitors. I recall logging off and back on recently to see if that would help. I checked the logs and found that I had done that on the 20th. I know I had the problem on the 21st & 22nd. Will monitor and update.
Also noticed a lot of activity posted in the logs throughout the day & night while not being used by me. There are no Windows Updates since 3/09/22 but I'm sure microsoft is surely doing something.
I have another computer, dual monitor, running Win10, which has never had this issue.