Silver Peak caves

[Poofer]

I'm playing the Steam version and i'm past the endgame, i'm visiting old dungeons to make sure i got all the loot and i stumbled upon the treasury of the Silver Peak Caves, the witch is supposed to drop a key but she didn't and i haven't been able to unlock it or lockpick it. Is it unlockable at a high enough level or did it bug out and i should forget about that particular room?

[Elendil / Redshift]

It's only unlockable by the key.

If you happen to have a save from before you fought the Mistress Employee, I'd be grateful for it. As far as I can tell when you kill her she should always drop the key. If I could find out what's happening maybe I can fix it (if there is a bug).

[Poofer]

Unfortunately, the save has long since been overwritten. I was only exploring the cave to get respawned loot after finishing the expansion.