I was playing on Yemen the other day and the enemy called in a stealth chopped. When I tried to take it down and it released flares, the missile ended up spiraling down to the ground and killing an enemy. First time I have ever seen this happen.
It's happened to me on Nuketown, an enemy tried to shoot down my Stealth Chopper and the missle was flared, flew into the air, and uncontrollably came down almost like a Hunter Killer Drone and killed me. It's pretty funny to be honest when you watch the kill cam.