Update:    Tenno: I need your help, WE need your help. There is a bug that is frustrating players everywhere - the invulnerable enemy bug. This problem is plaguing us like scarabs on the sands of Phobos. Most of us at DE have seen it in our own sessions, but reproducing it to nail down the exact fix has been extremely difficult. What exactly are we seeing? You get an enemy that can't be killed and there's no obvious reason why; in most missions you wouldn't notice but in a Defens