i'm not certain on the map, but it's an enclosed circular room with vex where you have to use the antenna to destroy the supplies bubbles. it's an area where you can fall to your death. well if you defeat one of the minotaurs i believe that holds the antenna it can drop to the bottom of the map and youre locked from getting it. it wont respawn. i'm not certain if this scenario happens when its your final/3rd antenna and no future minotaurs will spawn, or it happens even if its your first. i believe it'd be if its only your 3rd as the game may expect your team to not require any more antennas to complete the objective.