First, being in the Med, we use what's called camping gaz here.
they are in 2.7 kg tanks also commonly nown as french tanks.
they have a mix of butane and propane. Just the way it is.

As for a leak, I cleared the lines, and shut off a manual valve
last night. so, no gas possible. at 3 am, in cold, it came on.(the alarm)

Rickf
S/V Calaloo