Act 4 - The eternal nightmare bug - blocks transition to The Black Core

The Eternal Nightmare quest in Act 4 can be bugged.

Steps to reproduce:
1. Kill all three guardians of Malachai.
2. Interact with the black core door to get it open, but do not transition.
3. Transition out of the zone with the waitpoint.
4. Transition back, and ensure the instance is reseted.

The drops of the guardians do not drop / neither they exist in your inventory. Your transition is blocked by an error message that you have to kill the guardians.


Image
bug reference: 655716694

https://drive.google.com/file/d/1e7gEi3bxhceZSY3c6hIf1VflFVAbEJxo/view?usp=sharing

Upon killing the guardians again, the door will open.

Best regaeds