Abyss spawn in boss room, lost corrupted nexus quest completion status when I died

Bug Report ID: #602017976

Not sure if the abyss spawning on the boss is a bug, but I had 1 revive. I killed the boss and the abyss monsters from one pit. The corrupted boss spawned. And the abyss monsters came out of the pit around the same time. I died, and when I respawned, everything was gone but I got a notification saying I completed the map, and when i went to the atlas, I saw the map was green and the maps around were cleansed.

Note I didn't kill the corruption boss, only the map boss, and I was on the 12+ quest at the time - the quest did not progress.