Hey notnotmelon,
i try to reproduce this issue but i don't find a way to do this. but still this special Building stays connected to the grid, even through i disconnect it. Outside i see that Power Lighting symbol thats indicates here is no energy, but the powerpole on the inside is still connectet.
i try to build new buildings to test this but manually or with bots it still works as intented.
but i remember i had some problems with "more than 5 connections" at my prefab area, maybe its something like that. After that issue this i check twice that one Building has only 1 connection to the grid, in my playthrough its a medium powerpole with powerswitch ( fearsome CME´s ;) )
by the way its amzing ... yesterday i colonized my new Iridit Moon. I land i my space Capsule with 8 Buildings in my pocket with all the stuff i need (Power, Utilitys aso.) . I put them down and connect it together with the Mines and the cargorocketsilo and Ready.
greetings MoSII