Este é um bug no systemd, e é fixo no systemd 238, e possivelmente em versões anteriores.
[root@866d9b9835e0 system]# systemctl status foobar
* foobar.service - foobar
Loaded: loaded (/etc/systemd/system/foobar.service; disabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Sun 2018-04-01 21:06:21 UTC; 14min ago
Process: 143 ExecStart=/usr/bin/false (code=exited, status=1/FAILURE)
Main PID: 143 (code=exited, status=1/FAILURE)
Apr 01 21:06:21 866d9b9835e0 systemd[1]: foobar.service: Service hold-off time over, scheduling restart.
Apr 01 21:06:21 866d9b9835e0 systemd[1]: foobar.service: Scheduled restart job, restart counter is at 5.
Apr 01 21:06:21 866d9b9835e0 systemd[1]: Stopped foobar.
Apr 01 21:06:21 866d9b9835e0 systemd[1]: foobar.service: Start request repeated too quickly.
Apr 01 21:06:21 866d9b9835e0 systemd[1]: foobar.service: Failed with result 'exit-code'.
Apr 01 21:06:21 866d9b9835e0 systemd[1]: Failed to start foobar.
[root@866d9b9835e0 system]# systemctl --version
systemd 238
+PAM -AUDIT -SELINUX -IMA -APPARMOR +SMACK -SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN +PCRE2 default-hierarchy=hybrid
Você pode contornar o problema evitando o uso de Restart
no systemd.