Nightingale Legacy Portal
During the quest at the watch to enter a portal I entered the far right one and got to the second to last infestation killed all mobs and it did not let me progress to the vault. This happened while i was streaming so if needed i can back track and show what i did to ensure everything was killed.
This happens because one or more enemies seem to almost always spawn beyond the door leading to the next area, making it impossible to progress unless you are lucky enough that you can draw aggro through the door/walls and use explosives to finish them off.