Time Machine stopping due to screen saver wallpaper setting

I may have solved my problem with Time Machine stopping when the external disk “failed to eject properly” for no apparent reason. Sound familiar?

When I spoke to tech support months ago, they were also perplexed - but during the call, we could see a connection between Time Machine failing and the screen saver being invoked. Since then I went to the Lock Screen settings and set them all to “never” - but the problem persisted.

I finally found another screen saver-like setting that needed to be changed to “never”. It was buried in the WALLPAPER settings, hiding in the “advanced” settings. When I set it to never switch to using Apple’s built in screen saver wallpaper, Time Machine finally worked until finished without the external hard drive “failing to eject” properly.

Was it mere coincidence?

FYI: OS 26.1 on a macbook pro; Time Machine backing up to a 5TB Lacie external drive attached directly to a USB-C port.