No datasource found! How to debug this?

maas 2.9.2-9165-g.c3e7848d1 rfom snap (current stable)
I am getting this occasionally in some locations and consistently in others. IS this an ACL problem, a rack controller problem, or a rack<-> region controller problem?

I am blocked on debugging this because I am unable to add tags to enable serial console kernel params to the node (cannot enable it globally because it’ll break other builds). I filed a bug on that issue and posted about it in the UX subsection already.

Who has had this and how did you solve it? This is blocking a major upgrade of nodes due to this issue