pihole-FTL failed to create listening socket for port 53

Help
19

After a reboot, pihole-FTL does not work, and journal is empty. I have reproduced this several times now:

service pihole-FTL status -l
● pihole-FTL.service - LSB: pihole-FTL daemon
   Loaded: loaded (/etc/init.d/pihole-FTL; static; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:systemd-sysv-generator(8)
root@cube:/home/pi# journalctl -u pihole-FTL
-- Logs begin at Wed 2019-02-20 16:35:47 CET, end at Wed 2019-02-20 16:52:18 CET. 
-- No entries --

After restarting the service, pihole works as expected. No pihole-FTL errors in journal:

service pihole-FTL restart
root@cube:/home/pi# service pihole-FTL status -l
● pihole-FTL.service - LSB: pihole-FTL daemon
   Loaded: loaded (/etc/init.d/pihole-FTL; static; vendor preset: enabled)
   Active: active (exited) since Wed 2019-02-20 16:54:17 CET; 4s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 827 ExecStart=/etc/init.d/pihole-FTL start (code=exited, status=0/SUCCE

journalctl -u pihole-FTL
Feb 20 16:54:06 cube systemd[1]: Starting LSB: pihole-FTL daemon...
Feb 20 16:54:06 cube pihole-FTL[827]: Not running
Feb 20 16:54:17 cube su[880]: (to pihole) root on none
Feb 20 16:54:17 cube su[880]: pam_unix(su:session): session opened for user pih
Feb 20 16:54:17 cube pihole-FTL[827]: FTL started!
Feb 20 16:54:17 cube su[880]: pam_unix(su:session): session closed for user pih
Feb 20 16:54:17 cube systemd[1]: Started LSB: pihole-FTL daemon.

This seems to me in line with delaying the stubby.service for 30 seconds like mentioned here: