Kayle ult on Kog after death during passive

Was just in an aram as Kog with a kayle and during the heat of battle somehow I ended up dead, running towards the enemy with kog passive, with kayle ult for almost the entire duration of my passive. I believe I was ulted just as I died but this seems to be a situation that shouldnt occur. If Im invulnerable how did I die, if I was dead how did I get ulted?