Desktop wallpaper keeps changing while computer is idle

I have an issue where when my monitors turn back on after a period of inactivity, the desktop wallpaper on the second monitor reverts to the default (presumably because the second monitor takes a few seconds longer than the first to turn on). It doesn’t happen every time but often enough that it’s become annoying. It’s never happened after a reboot, only when waking the monitors after I’ve been away from the PC.

So far, on the advice of various posts (which were all about this happening after a reboot, admittedly), I’ve tried disabling KScreen and changing the Desktop Session settings to “Start with an empty session” but neither had any effect on the issue.

In case it’s relevant, I’ll also add that initially when this happened any open windows on the second monitor would get moved to the first but that stopped happening once KScreen was disabled.

As an update to this, the last time it happened I just left the wallpaper as the default and after waking the screens today, the second monitor has no wallpaper at all - it’s just black.

It’s probably todo with monitor/display detection. It doesn’t recognize it as the same display and registers it as a new/different one instead. Essentially, this’ a bug, sorry. I don’t think there’s anything you can do about it via configuration.

From your profile description:

So why not using the video-nvidia for that GPU? Also, are you running wayland session?