Comment 58 for bug 1890858

The fix is in Focal and Focal only as that is where the problem occurs.
As the old bug stated, this doesn't affect later Ubuntu releases.

You said that the customer reported that
  network unix dgram,
works, would you mind asking to try if the more restrictive
  unix (bind) type=dgram addr=@userdb-*,
would also work?

The Openstack team could then add that onto the backports they provide for Focal.
Adding a bug task for the cloud-archive.