It is a matter of unbalanced mixture of gas and oxygen. The piezo ignites only when the correct mixture is achived just like the ignition system in engines. Try the gas level in minimum, sometimes it works.

I use a piezo pocket torch for many years and I am a dedicated smoker I always have back up for fire purposes. Also my torch can be lit with a flint rod etc. when needed as it has a flame lock that leaves both your hands free. It is not to fit in a PSK but it is an important piece of equipment for me.

rothenberger pocket torch for outdoor soldering

Burak