All of the warlocks who died had their self res powers pulled into the essence of ir yut

The way I see it there are two possibilities - the cool one and the likely one. The cool one: Just like Oryx was able to resurrect his sisters even after killing them in the sword world, by creating their shapes in the living world. It's possible that this can be done for any Hive; they cannot be permanently killed except by their own worms consuming them, or by all who know their shape being killed as well. Someone brought her back in the same way. The likely one: Bungie goofed.