Run the System File Checker to repair any potential corrupted files
Open Command Prompt as an administrator and run the below command
sfc /scannow
Wait until process completes
>Go to Settings > Personalization > Background
Ensure that the background is set to Windows Spotlight.
If you’re using Picture or Slideshow, switch back to Windows Spotlight.
>Go to Settings > Personalization > Lock screen
Switch from Windows Spotlight to a different option like Picture or Slideshow and then switch back to Windows Spotlight.
Reboot your pc. See if the issue continues.