Après plusieurs reboot ça tient.
Vu que je n'ai pas utilisé l'option
--runtime
je n'ai pas de soucis.
--runtime
When used with enable, disable, edit, (and related commands), make changes only temporarily, so that they are lost on the next reboot. This will have the effect that changes are not made in subdirectories of /etc/ but in
/run/, with identical immediate effects, however, since the latter is lost on reboot, the changes are lost too.
Similarly, when used with set-property, make changes only temporarily, so that they are lost on the next reboot.
J'ai l'explication du pourquoi disable n'était pas suffisant :
https://askubuntu.com/questions/816285/what-is-the-difference-between-systemctl-mask-and-systemctl-disable
Disabling the service deletes the symlink, so the unit file itself is not affected, but the service is not loaded at the next boot, when systemd reads /etc/systemd/system.
However, a disabled service can be loaded, and will be started if a service that depends on it is started; enable and disable only configure auto-start behaviour for units, and the state is easily overridden.
A masked service is one whose unit file is a symlink to /dev/null. This makes it "impossible" to load the service, even if it is required by another, enabled service.