I always start my fridge on shore power 2 days in advance, I load it up a day before, and watch it, on the day I leave I unplug it from shore power, then I run in and make sure the fridge "lit".
If it doesn't light, the led will flash and you have to turn the fridge off and then back on to make sure it is lit.
It is easy to unplug the shore power and just assume it will start up on propane.
Many Things can happen, air in propane line, misfire etc, so you have to make sure it is going and not blinking before you pull out.
I always check it while on the road. We usually eat all our meals in the camper on the road.
2016 Shamrock 23WS