Mine goes off when I have the camper plugged into shore power for a while. Otherwise it works fine. This was with the original unit as well as a replacement.
I have equated this to high voltage and or some odor from the power converter/fuse box that is directly across from the propane sensor.
I have checked with a propane detector and there is not propane around when it is going off like this.
I have been meaning to put a switch to the sensor, but for now I pull the fuse.
I hope this helps.