My former Classic 25 had a strange habit. If the trailer had been stored for more than a week, the fridge would not light and, like you, I could smell propane. I would remove the shielding, prop a lighted lighter in place, and go inside to push the button again. I had cut a little block of wood that would keep my stove lighter burning hands off.
Once lighted, we could go on a month-long trip and it would switch back to propane seamlessly each time we broke camp.
Store it for a week or so and it wouldn't light again!
The cooling unit finally died and the replacement worked OK every time. Apparntly, the electronics had to warm up for a time before it would spark.
John W. Irwin
2005 Classic 28 "Sabre-Dog III"
2013 Silverado 2500HD Duramax/Allison LTZ
WBCCI #9632, TAC TX-10