Cloak & Daggers glitch

[LordMaim]

I've gone through the whole objective list for Cloak & Daggers, but it won't let me complete the "Neutralize All MCB Opposition" objective. I've neutralized everyone in the room, but no dice. There's a marker on my screen but nothing shows up on my map, and when I try to go to the marker, it moves. First it's somewhere near Derelict Row, but when I go through the tunnel, it changes position to be somewhere in the roof of the storage locker right at the end of the tunnel. As a result, I can't complete the mission. (PS3 Version)