It might have to do with the 120 volt power supply, not in most RV's while dry camping, and the lack of ability to run the system on a cold night. Many will turn on at 35F to keep it above freezing.
You can plan on installing a drain adjacent to the unit to completely drain the water heater before driving on a freezing day. Even driving will bring a lot of outside air through the heater, completly freezing the water solid on a 30F day. This can burst the pipes, and of course freeze damage is not a "Warranty defect". Also if the unit does try to cycle on while in a moving RV - who knows where the flames will go or get pushed by wind? So if it has not been tested, I would not allow it to go into a RV if I was the designer.
Maybe they have tested them, and the compartment got to warm around the heater while driving the test RV.
Fred.