Sounds like pulse jet? Propane bottle cools very rapidly when high rates of propane are evaporated.
On my boat I wanted to get rid of an old propane bottle, but it was full. So I opened the valve and let it fly.
Very soon the bottle started freezing on the outside, and the propane coming out slowed down.
I submerged it in the lake, but all I got is more ice on the bottle ? It took long time to empty it..
Live and learn…..