Not sure if bug or timing quirk

[srmalloy]

I had the "Defeat Hades and guards" mission from Lawrence Mansfield on my Poison/Dark Defender, and I was snipe-warrioring my way through the mission until I found Hades alone in a back room on the second floor. I sighted up on him and lit him up with Moonbeam. He started his monologuing about how his ring made him invincible as my shot went off... and I one-shotted him, getting the XP for defeating him, the 'mission complete' announcement, the mission-completion XP, and the mission exit button. Then, while continuing with his "the ring has stopped working" and "Noooo!" exclamations, he stood back up at half health and started throwing fire at me. I took him down again, and got a second tranche of XP for defeating him.

 

I'm not sure whether the game doesn't account for someone being able to one-shot him before whatever effect of the ring (looks like just a big heal) takes effect, or if it's just lag that kept the heal from going off until after he'd been flattened.