Problem with the enemy NPC deaths

I made a new scene and only one enemy NPC can be damaged and whenever I kill it, some of them the others die too while the rest can't be damaged . I've had the same problem on the previous level but I don't remember how I solved it. I'd really appreciate some help

Edit: It turned out I had several identical CCs installed , so I just had to go into project content and get the NPCs from the first CC