Puffy ack tags your ID i guess you could say. Once it starts shooting at you it never forgets as long as your able to keep flying for that sortie.
I thought the range was 15k but could be wrong. I do know that auto puffy will not shoot at you unless your above 3k. Once you pop above that alt though, it will immediately start shooting at you again no matter who is closer or higher. In other words, it will shoot right past the guy who was not tagged yet to try and kill you first. The only way to beat it is to get out of it's range or re-up in a new plane.