I was playing co-op on an underwater mission. the game was going fine until we reached the boss. We got its health down by about 15 percent. it then moved towards the furthest right out of player reach. It was still able to attack us with its guardian beam and summon guardians. the guardians also stayed behind the walls. They couldn't hurt us tho. We tried to get as far away as possible, we purposely killed ourselves, but it wouldn't move. we had to return to camp. Please fix this, thank you for taking the time to read this.