Hi. I just bought a Pocket Rocket 2 and a MSR 4oz gas canister. I just tested it out before going to Glacier National Park next week. When I attached and detached the canister a couple of times there was some gas leakage each time (while I was screwing the canister on and unscrewing it). I live at 4,000 feet. Is this normal?
I am perplexed. As mentioned earlier, either a stove or a cannister issue. Try another cannister, and if the problem persists, I think it would be the stove. Also, make sure the stove is in the "off" position when attaching it to the cannister. It is possible that the stove was in the "on" and even full blast positions so fuel went where it was supposed to, out through the nozzle.
Was the valve open? If that is the case, close it. If you connect a open pipe to a pressurized container, you will get something moving through. Most likely the white is the frozen condensation from the pressurized gas.
Either you have a stuck open valve, or you screwed an open stove to a pressurized canister. That is the only way you will get gas through the stove top.