Dying to boss during Delirium Mirror event deletes everything on the map

As stated in title.
It's happened a few times where:
I will run a delirium mirror found inside of a map
Work my way towards the boss to fight it with the delirium effect still in process
I would die (git gud lol)
Respawn at checkpoint
Kill the boss, go back to clear the map
Map is reset, no monsters on map, fog of war is reset along with map build
Absolutely nothing else in the map
No monsters I walked past to get to the boss, no drops, just completely empty.

I think it's a bug and unintentional.

its not a delirium thing

if you die to the boss, everything will be gone

Oh shoot now that you mention it I do remember the warning message that pops up
My mistake, carry on