Comment 5 for bug 1892029

A message was logged in the /var/log/juju/machine-#.log file on the unit's machine. Not available via `juju debug-log` like other messages.

machine-0.log:2020-10-22 20:08:11 INFO juju.cmd.jujud machine.go:649 Reboot: Error executing reboot: exec: "at": executable file not found in $PATH.

There should be a better way to uncover this.