Odd behaviour when instatiated

I'm using this script as part of a prefab, which I then instantiate in another script

 using UnityEngine;
 using System.Collections;
 
 public class MyCollisionGenerator : MonoBehaviour
 {
     private GameObject headBone, weaponBone, bodBone;
     private SphereCollider headSphere, weaponSphere, bodSphere;
     GameObject[] Fighter; 
     public FighterScript char1Script, char2Script;
     private bool failSafeVar = true;
 
     void Start()
     {
         Fighter = GameObject.FindGameObjectsWithTag("Fighter");
         foreach (GameObject bone in Fighter)
         {
             if (bone.name == "head")
             {
                 headBone = bone;
                 headSphere = headBone.AddComponent<SphereCollider>();
                 headSphere.radius = .2f;
                 headSphere.isTrigger = true;
             }
             if (bone.name == "WeaponBone" || bone.name =="Weapon_R")
             {
                 weaponBone = bone;
                 weaponSphere = weaponBone.AddComponent<SphereCollider>();
                 weaponSphere.radius = .5f;
                 weaponSphere.isTrigger = true;
             }
             if (bone.name == "spine1")
             {
                 bodBone = bone;
                 bodSphere = bodBone.AddComponent<SphereCollider>();
                 bodSphere.radius = .3f;
                 bodSphere.isTrigger = true;
             }
         }
       
     }
 
     void Update()
     {
         if (weaponSphere.bounds.Intersects(bodSphere.bounds))
         {
             if (failSafeVar == true)
             {
                 if (animation.IsPlaying("AnnaHammerJab") &&
                    animation["AnnaHammerJab"].time > .5f)
                 {
                     failSafeVar = false;
                     Debug.Log("-1 health");
                 }
             }
         }
         else
         {
             failSafeVar = true;
         }
 
     }
 }
 
 

If I pull the prefab character into the scene, the code works fine, I can even instantiate then player, and pull an opponent in.

When I instantiate the enemy, however, the code stops working, despite the enemy having all the correct spheres for collision.

Can anyone see why?

PS - I edited some old code out of this for clarity.