You now have a leak that you can smell and A small leak and the bad smell goes away and leaves you with a camper full of explosive gas so find the leak B 4 you put the camper away for the winter.
Try the soap and water. If you get a propane person they have an electronic sniffer that can narrow it down.
Whet ever you do _ Do Not wear anything that can make a spark or turn on or off any electronic item or
light any matches.