I was puzzled that nut-server.service was not starting on my
workstation. I had
installed it to use with HomeAssistant.

I tracked it down to the service file not requiring
network-online.target, but
only network.target.

I replaced all the instances of network.target with
network-online.target and
now the nut server starts correctly every time.

I checked nut-server_2.8.1-3.1+b1_amd64.deb and nut-server.service still
only
uses network-online.target

This may slow some installations that have static IP assignments.