This is a general problem with Necromancer I think. Many times I will die and be presented with the respawn option on the screen, yet my minions will finish off the boss after. it’s usually not a problem except with monolith bosses it’s a major issue.
I died to emperor of corpses for instance and my minions killed him a few seconds later. It then gave the option to change my blessing even though I had died. I was forced to pick something and this closed out the timeline. Basically no way for me to get my loot for the hour or two of work building up the timeline. Very frustrating.