Boss Loot Deleted From Simultaneous Death

2/27/2025: Beat the area boss in Mawdun Mine (can't remember her name, the one who shoots grenades everywhere) in Cruel Act 2 but got one-shot just before she died. Her death animation played, the caged NPC played her post-fight dialog, and loot dropped from the boss including an Exalted Orb. Upon reviving immediately outside the arena, the boss' death scream played a second time, and all loot she had previously dropped was no longer there. She did not drop any new loot.

Double-checked to make sure it wasn't due to label toggling. Neither labels nor item models are present. Revisited the rest of the map to see if the items had moved somewhere else, with no luck. Also found that previously abandoned loot on the ground throughout the rest of the map was no longer there, and some packs of monsters in previously cleared areas seemed to have respawned (including a stationary minecart NPC in one particular spot, who in both run-throughs failed to aggro or attack). Almost seems like upon respawning the instance was partially reset - map layout remained the same with fog of war still revealed, but dropped items were removed and enemies were partially replaced.