Gawd I hate systemd. It is turning Linux into a blend of VAX/VMS, OS/360, and MS Windows. Here's the latest gobldygook nonsense when I was the only user logged in:

karl@prime-radiant(53): reboot
Operation inhibited by "akmods" (PID 32776 "systemd-inhibit", user root), reason is "Akmods Transaction running".
Please retry operation after closing inhibitors and logging out other users.
Alternatively, ignore inhibitors and users with 'systemctl reboot -i'.