Killed The Executioner, died at the same time, loot disappeared

I killed The Executioner but his guillotine got me at almost the same moment. I could see the loot he dropped on the ground, but couldn't pick it up of course because I was dead. After respawning at the checkpoint, all the loot was gone. Not sure if that is working as intended or a bug?

The world map shows that I successfully killed him so I believe that means there won't be any loot for killing him again. Seems to me if the game says I killed him then the loot should persist through my death so I can get it.

This exact scenario just happened to me. The executioner does his insta-kill large AOE Drop. As he was casting that, I defeated him - but his death didn't stop the cast. He dies, I die, I respawn at checkpoint and all loot except an uncut skill gem is left.