Touble getting rack controller assigned to vlan

[tessa]

seems like this is probably related to the rack controller issues I had last year about this time:

Maas 2.9 snap bug: can't enable dhcp, get "A primary rack controller must be specified."

I seem to have run into this bug: has anyone seen this before, and can perhaps advise how to coerce maas into working correctly with the v2.9 snap on 20.04 with zfs root?