I had problems with Acmar's Disruptor. Neutral building Domains: 3, Flux cost: 4. Ukeep (1). No flux is drawn from flux wells.

The problem is that sometimes it survives a lot of turns without paying any upkeep. But suddenly, one turn , it is destroyed without asking if you want to pay its upkeep.

Yeah it is a little broken. Basically it gets paid automatically. So if you end the turn with no flux it can't pay for it.
I'll change the way it works soon.