Comment 17 for bug 1902960

> systemd-udev-trigger service didn't correctly run at the proper time to generate uevents for existing devices

note: as systemd-networkd did correctly associate the .network file at first, my guess would be during boot the .network file was different than it is when boot is finished, which is why a restart causes networkd to remove the match. Only a guess, however - i haven't looked any deeper at what magic is being done by cloud-init.