A similar suggestion to the other poster:
Try relocating one of the troublesome units to someplace nearby but not mounted to the ceiling. The top of a bedroom dresser, the floor, a bathroom countertop, the top step of the stairs, halfway down the stairs, hanging from a wall (picture hook)… just get creative.
And since you haven’t mentioned it, I presume these are all smoke detectors? Do you have any heat detectors or carbon monoxide detectors installed?
That’s one thing I noticed about NZ, during my first trip: the speed limits are generally sane. If anything, the rural speed limits have a genuine sense of reality to them.
In stark contrast, driving in Canada (Toronto area) and the US (Texas) most times I felt I could safely go faster, were it not for the constant threat of speed traps or random / stealth cruisers.
In NZ if you’re doing a long drive and you don’t heed the slower speed limits as you enter a bend in the road, you may have just fucked yourself. Especially if the roads have a layer of moisture, which is likely.
And the more built up areas have a decent amount of traffic calming, which is nice.
Toronto and really all of the GTA need a severe dose of NotJustBikes to get sorted.