Auto Attacks going off in GA(Guardian's Angel)

This happen to me in a ranked game recently. We were team fighting> We focus there Vayne(Which has a GA)> She goes down> Our Lucian has 2/3 Silver bolts so he is about to die.>> As Vayne was dead and about to be resurrected. I see an auto attack fly from her(While she is dead still) to the Lucian killing him. I am not sure if anyone else has experienced this, but this sure did ruin a team fight. Lucian ended up dying from that one Auto.