That's a different death. Spirit ignition happens every round at about the same time. Drakeeh does the animation that starts the "ghost pahse". Then you start collecting ghosts. A few seconds before he does spirit scream he does this.. It's like the ghosts all zap(lack of a better word) at the same time. The times I died I was in the circle with the gold ghost but right before I picked it up. So it seems that if you have a ghost on you, less than 3, and you are getting another one but not quite there this "ignition" happens and you take damage. Sometimes i died and sometimes it reduced my health by 80 percent.