Scenario: Debian 13 Trixie, wake-on-lan enabled, poweroff command in cronjob.

The poweroff command is executed, but it turns out to be a reboot instead. The poweroff command works as expected if executed from the terminal.

The solution was to execute /usr/bin/systemctl poweroff instead of /usr/sbin/poweroff. Here it is the cronjob entry:

# Auto poweroff after weekly backup.
20 17 * * 5     root    /usr/bin/systemctl poweroff