Almost same thing happened to us in 2012.
New Aug 2012 spent 4 days at a local Corp of Engineers campground.
Took it back the next week for minor warranty work and a refill of the empty propane tank.
Dealer said they ALWAYS leak test twice!
As I was shaking the hose at the tank I said "do they test it while rolling down the road?" He said WOW as he jumped out of the large white cloud
.