In YaST repositories I've run into warning dialogs like the following:

Warning
Repository 'OBS AF Kernel:stable:Arm' is managed by service ''.
Your manual changes might be reset by the next service refresh!

To reproduce, run yast repositories, add a new repo (custom URL from OBS),
afterwards select it in list of repositories and change the Priority. This
dialog will come up once, but not on subsequent changes, not even after
restarting yast.

Looks as if some service variable is checked for null rather than empty-string?

This did not happen a few weeks/months ago.