So I have killed all 12 hunters but only have 7 Ivory keys. I have gone with friend to help them but no key. First question WHY! Next question how do I get it.
Fix the game, it is too good to let it turn to crap.
Washington monument settlement loot room to activate tv screen of red circle
Go into Photo mode to check time is after 1900 and before 0500 .
Go outside, stand in red circle.
When I did it, I all ready had mask just needed last key.
The drop was high end item plus key
So I did what you said, I went down the rope to activate the button and it wouldn't activate. I had to fast travel out and come back. Then it did activate but it is the same thing, I have not seen the hunter on my map since I killed him.
Went back a second time and could not activate the switch. Went and found patrol, let them kill us. Then we could activate the switch and killed the hunter. Still a little buggy but done.