http://www.kettering.edu/~lpgvan/SAE-LPG.html
Great Reading ~!
Yeah, that is good! Makes my old-fashioned carbureted system seem laughable.
It mentions "conversion" of the LP/air mix in the manifold leading to combustion in the manifold due to heat soak when off. Never heard of anything like this from anyone anywhere; maybe it's peculiar to very compact, modern, front-drive systems. The 232's intake system does heat-soak, but certainly not up to ignition temperatures.