More than likely the right hand thermostat, clix on, is not making a connection during cool down of the heater. That should close as the heater cools to call for relighting.
If you have an OHM meter and while the heater is cool remove the 2 brown wires and check for continuity across the thermostat. If it is open that is the problem. Not as likely but also remove the red wires and check that one also. Booth should be close while the heater is cool.
If one is bad replace as a set.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles