Groups with groups cause: undefined is not an object (evaluating 'i.length')

HI, have several groups with nested groups that cause the error: undefined is not an object (evaluating ‘i.length’) and seem to have the state unknown.

Group with need groups:
47

error in the inspector:

if I put a single switch in the main group Floorplan wing, the issue seems resolved. I dont want to do that though, since it takes away the whole idea of the setup…

Anyone who can shed some light please?
thx.