Zombies dieing out and not respawning?

[Sylent]

Hey guys I was wondering if anyone fully understands what causes a zombie to die out and not respawn. I've been trying to figure it out since Black Ops 2 was released and I just can't seem to wrap my head around it. So if you know how to keep a zombie from doing this please help.

[MysteryMachineX]

Only completely undamaged zombies respawn. If it has been shot even once, it will not respawn. It will just die.

Now, there does seem to be a glitch were this doesn't happen. I'd say about 1% of the time where you decide to leave a zombie, it will just die, even if not hurt. This happened a lot on Great Leap Forward for me. However, it was rare, so we didn't worry about it. We were just aware of the possibility, however remote.