How can we debug systemd-gpt-auto-generator failures?

["Kevin P. Fleming" <kevin@xxxxxxx>]

I've got two systems that report a failure (exit code 1) every time
systemd-gpt-auto-generator is run. There are a small number of reports
of this affecting other users too:

https://bugs.archlinux.org/task/73168

This *may* be related to the use of ZFS, although I've got a
half-dozen systems using ZFS and only two of them have this issue.

Running the generator from the command line also produces exit code 1,
but doesn't produce any output. is there any practical way to debug
this failure?