Well, from my understanding just V3 trigger glitchieness is pretty common in general. But what it's done is that when I first got it, it would be shooting semi and then decide it wanted to go full auto for a few seconds. No big deal. Put the gun on auto and let out a 2 second or so burst and it usually went back to normal.
The other thing was that it just doesn't like going to semi auto. I have to go to full auto and then back to semi. No big deal though. At first I thought it was that I had spun the trigger gears off their timing when I put it back together but I fixed that as best I could and it still doesn't work quite right. Just a little nuisance. I don't usually use semi auto anyways.