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?
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?