Quest Glitch "Last Drink" ??

So i'm doing one last drink.

I went to B first I think, the one girl who thinks the captain wants to kill her.

Then i went to A i think which is Kowha, that's where i'm having problems. He wants me to kill all the zombies in the settlement, cool no problem. Except i go kill them and i never get the Check that i killed them all. I killed all the guys you jump down to fight, then i killed the upper guys you climb the ladder to get to. all dead.

Trust me,i've run this mass murder part a half dozen times now different ways at NEVER do i get this checked off. WTF?? And Kowha won't talk to me until it checks.

I noticed some of these guys make a circle on the ground and then disappear. Do they teleport or are they escaping that's the only variable i dunno what's going on if any are escaping?

I dunno, frustrated right now. Anyone else had problems with this quest? Playing on XSX.

EDIT: One solution i found was forget about this quest for now play the rest of the map and the main story will have a choice. If you pick Sever the Adra, Kowha will be killed as part of that process and there will be a note on his body you can take to the captain. That of course locks in your choice if you want to complete One Last Drink.