Sounds like the Circuit board is going bad. The circuit board uses either a flame sensor or a thermo-couple to sense if the flame is there, if not it shuts the gas valve. If the flame stays lit, the flame sensing circuit is working and the gas valve is doing its job keeping the reefer running. That leaves the ignition circuit not receiving the message it is no longer needed and the circuit board controls that function. I would recommend replacing the OEM board with the Dinosaur brand board, there are few complaints compared to the OEM replacements and the OEM board might not even be available anymore due to age of the unit.
1995 Gulf Stream 34' Scenic Cruiser Diesel Pusher 8344WFD. Cummins 12 Valve 230 HP, Allison MD3060 World Tec II.
2019 Jeep Cherokee TrailHawk Elite,
Road Master Sterling All-Terrain Tow Bar,
Air Force One Brake System