operator error is always a favorite scape goat for a mfg to sway the liability away from them. Sad but true...

i just recently had an issue with the same thing, bad converter, removed the cover and found a bent reed and damaged square rubber pad on the reed. This truck has been running for years though with no issues till now. The one thing i noticed and have noticed in several converter changeouts is the amount of oil accumulating in the converter from the LP Gas. This oil is very damaging to any rubber/neoprene parts and will emminatly cause failure.
The only fixes i know of to cure this problem is:
A) to be continuously cleaning the converter at every PM service(mfg's and dealers alike are suggesting this as part of a pm now)
B) Change LP Gas suppliers

Apparently not all LP Gas suppliers are created equally, some have more oil content in thier lpgas than others.
They dont want to see it as an issue apparently.