Dometic fridge shuts off overnight (propane mode)

Any of the above issues might be the problem.

Or erratic igniter? Mine sometimes sparks, sometimes doesn't. If I keep retrying, it eventually sparks. If the "doesn't" time occurs during the night, without you there to retry, it would stay on check light.

Mine has never had problems with high altitude, even up to 10K. The one time it went off on a cold night, around 30 degrees, the problem turned out to be the propane regulator.