Verified unattended-upgrades 1.5ubuntu3.18.10.1 on cosmic:

root@cc-lp-1806487-uu:~# /usr/share/unattended-upgrades/unattended-upgrade-shutdown --debug
root@cc-lp-1806487-uu:~# tail /var/log/unattended-upgrades/unattended-upgrades-shutdown.log
2018-12-19 18:29:38,461 WARNING - SIGTERM or SIGHUP received, stopping unattended-upgradesonly if it is running
2018-12-19 18:32:11,165 WARNING - Could not get delay inhibitor lock
2018-12-19 18:32:11,165 DEBUG - Skip waiting for signals, starting operation now
2018-12-19 18:32:11,166 DEBUG - Starting countdown of 25.0 minutes
2018-12-19 18:32:11,166 DEBUG - Initializing apt_pkg configuration
2018-12-19 18:32:11,167 DEBUG - get_lock returned 9
2018-12-19 18:32:11,167 DEBUG - lock not taken
root@cc-lp-1806487-uu:~# rm /etc/systemd/system/systemd-logind.servicerm /etc/systemd/system/systemd-logind.servicerm: cannot remove '/etc/systemd/system/systemd-logind.servicerm': No such file or directory
root@cc-lp-1806487-uu:~# rm /etc/systemd/system/systemd-logind.servicerm /etc/systemd/system/systemd-logind.servicerm: cannot remove '/etc/systemd/system/systemd-logind.servicerm': No such file or directory
rm: cannot remove '/etc/systemd/system/systemd-logind.service': No such file or directory
root@cc-lp-1806487-uu:~# rm /etc/systemd/system/systemd-logind.service
rm: cannot remove '/etc/systemd/system/systemd-logind.service': No such file or directory
root@cc-lp-1806487-uu:~# systemctl daemon-reload
root@cc-lp-1806487-uu:~# service unattended-upgrades restart
root@cc-lp-1806487-uu:~# service unattended-upgrades status
● unattended-upgrades.service - Unattended Upgrades Shutdown
   Loaded: loaded (/lib/systemd/system/unattended-upgrades.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2018-12-19 18:33:11 UTC; 7s ago
     Docs: man:unattended-upgrade(8)
 Main PID: 3164 (unattended-upgr)
    Tasks: 2 (limit: 4915)
   Memory: 8.5M
   CGroup: /system.slice/unattended-upgrades.service
           └─3164 /usr/bin/python3 /usr/share/unattended-upgrades/unattended-upgrade-shutdown --wait-for-signal

Dec 19 18:33:11 cc-lp-1806487-uu systemd[1]: Started Unattended Upgrades Shutdown.
root@cc-lp-1806487-uu:~# tail /var/log/unattended-upgrades/unattended-upgrades-shutdown.log
2018-12-19 18:29:38,461 WARNING - SIGTERM or SIGHUP received, stopping unattended-upgradesonly if it is running
2018-12-19 18:32:11,165 WARNING - Could not get delay inhibitor lock
2018-12-19 18:32:11,165 DEBUG - Skip waiting for signals, starting operation now
2018-12-19 18:32:11,166 DEBUG - Starting countdown of 25.0 minutes
2018-12-19 18:32:11,166 DEBUG - Initializing apt_pkg configuration
2018-12-19 18:32:11,167 DEBUG - get_lock returned 9
2018-12-19 18:32:11,167 DEBUG - lock not taken
2018-12-19 18:33:11,800 WARNING - SIGTERM or SIGHUP received, stopping unattended-upgradesonly if it is running
root@cc-lp-1806487-uu:~# dpkg -l unattended-upgrades  | cat
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                Version            Architecture Description
+++-===================-==================-============-===========================================
ii  unattended-upgrades 1.5ubuntu3.18.10.1 all          automatic installation of security upgrades