Cannot complete Strength in numbers

Platform:** Xbox 1

Steps To Reproduce:
I have restarted the game, fast traveled in and out, I have even traversed the whole island killing everything I see. Yet I cannot complete this quest because I need to “clear the area” I’ve checked the bunker above it and in it killing everything to no avail. Please fix this. It’s stalled me out
Images / Videos:

Host or Client:
Host multiplayer lobby
Players in your game:
2 to 4 all friends