I don’t buy the idea that run of the mill (inexpensive) butane is inferior. I have a Butane soldering iron, I bought it from Radio Shack in 1979. I refill it with whatever is the least expensive sold at stores, it’s still working like new. I have also used the same butane in lighters over the years and had the lighters fail. If it’s the butane that is the problem, why does it work in my soldering and also a small Harbor Tools torch I have had for years?

Deductive reasoning and my experience says it’s the lighters and not the butane.