[Nut-upsuser] UPS is not turned off in slave-only configuration?

[André Hänsel]

I have two hosts.

One is the ups-server. It's generator powered and can be assumed to never go
down. This is the one that all the UPSs are connected to. It has:
- the UPSs configured in upsd.conf
- a "upsmon master" user in upsd.users
- an empty upsmon.conf

The other one is server-1. Its upsmon.conf contains:
MONITOR test-apc at ups-server 1 monuser blah slave

Now, what I see is that when the UPS feeding server-1 goes LB, server-1 is
indeed shut down, but it seems that the UPS is never switched off.

This is a problem because when power is restored after shutdown, but before
the battery runs out (with no load, it continues for quite a while),
server-1 is not rebooted.

Is my configuration wrong? How can I help diagnosing this problem?