A tale of two stoves: This little stove went to Denali. This little stove should have stayed home. This little stove wouldn't light at 17,000 feet. This little stove was returned.
In this case there were two of these little pigs. My climbing partner and I each bought a Nova multi-fuel stove. Long story short, they both began to fail intermittently starting at 11,000 feet and both failed completely at high camp. We tried everything we could think of to get them to go, until some Brits took pity on us and loaned us their MSR Whisperlite to melt snow for water. Kudos to the MSR, which got to a rolling boil in no time.
To shut off the flow of fuel you flip the fuel bottle over, and I suspect this mechanism was the cause of the malfunction. Nova means "it doesn't go" in Spanish, and that accurately describes this stove's high-altitude performance.