this is the latest version of windows 10 (all updates installed as of this date)
Screensaver in use is not a native Windows 10 screensaver. it is called "Endless Slideshow" and can be found at https://www.free-photo-screensaver.com/

usage in this scenario is the command line tool, and the mobile app. (using command line tool with google home mini to execute commands in windows)

If the computer is sitting at the lock screen, or windows has turned off the screen, the commands work perfectly, switching between monitor configurations in both usage scenarios.

If the screensaver is actively running, i hear an error sound in windows, and when I unlock my PC, I find the error in the attached screenshot... (also in both scenarios)

Let me know if you need more information.

Edit: The img bbcode tag on here doesn't seem to support PNG files.

It does the same thing using Ribbons, and any of the DF screensavers. Additionally, when using a DF screensaver, I'm forced to use ctrl-alt-del after ending the screensaver, because i'm left with a blank screen otherwise.

i hope you do figure it out, because with my issues, sometimes i need to change the display, without being able to get to my keyboard or mouse right away.

Only other option would be to just disable the screensaver, but I'd rather not, if i don't have to.
I look forward to hearing the results though. good luck!

Been a while since I've seen this problem. Got an update for you. 9.4.3 is randomly doing this if the computer is locked, whether the screensaver is active, the lock screen is visible, or all displays are blanked (system idle).

sometimes I only have to do it once, and other times, I have to unlock the PC, and manually do it myself.

If I close the error window after I've changed display configuration, it reverts it to the previous configuration, and I have to change it back.

This happens almost exclusively using the command line method (Google home mini)