Asg m9 co2 blowback issue

[Shad0z7]

Well. After about 1 magazine this happens. 

Any answers would help. I tried to get a warranty repair from my seller some time ago. Had the gun for about a month. Supposedly fixed. But still. The issue persists

Would could cause this?

[AK47frizzle]

I've seen this kind of problem before, but on a g18c: it's the valve inside the nozzle getting stuck and then unstuck every 2 shots. Either the spring is the issue or the valve itself is mangled. But then again, I only know this from a g18c. Maybe it's entirely different on the m9 system.