Upon recreation of the behavior, it was noted, that the RequiredBy-statement was placed in the [Unit]-section. When moving it to the [Install]-section, expected behavior was seeen.
To clarify: 1) Starting point: two enabled services A & B with no connection 2) Change of A.service -file by adding RequiredBy=B.service (while A.service is enabled). 3) systemctl enable A.service ---> symlink /etc/systemd/system/B.service.requires/A.service created as expected 4) all good no bug present, behavior as expected Expected behavior could be reproduced with the original services, as well as test services. Bad behavior can be reproduced when putting RequiredBy=B.service in the [Unit] section of of A.service only (in that case the symlink is not created upon "systemctl enable A"). Kindly close and mark as wrongly reported. I will pay more attention and do proper testing and reproduction before reporting in future. My apologies. Thank you.
