My temporary fix was to replace the plastic Acme (QCC) fitting and its pigtail with a brass POL fitting and a short length of hose. I had the short length of hose with a POL fitting on each end onboard. I use it to decant propane from one bottle to another. It comes in handy when the only available propane is cylinder exchange. I don't want to give up one of my 20 lb aluminum
cylinders. Back in the US, I replaced the POL fitting and hose with another Acme fitting and pigtail.
The newer Acme fitting has some additional safety
features, "Acme nuts contain a thermal bushing, which will melt in a fire, and prevent the escape of gasses from the tank. When it melts, it allows the new OPD spring activated shut off valve, which will only allow the flow of gas if a fitting is attached, to pop out and completely shut the flow down. They also have an improved excess flow check valve, compared to the valve in the old POL fitting" (and my POL fittings have no valve -- they are bored straight through, and the quote was from the internet).
Anyway, since no one has seen another Acme connector fail, I'm "pretty" happy with it.