That's a bug (IMHO). I had to open an SR to get through making it work.
We did a lot of things, and I've been working with support on three or
four different SuMa SRs. Minimally, you have to be on the latest version
of SuMa, the latest patches for the Minions, and there are some
(otherwise undocumented, as far as I can tell) Minion configurations that
have to be applied.
We have the latest SuMa installed and therefore the latest salt version for the minions. Guess we'll have to open a ticket to figure out how to make this work.