1 out of 4 objects with the same script that reference the same transform list returning null?

Hi, i have 4 Gameobjects (turrets) with this same script attached which use a list of Transforms as targets. The Coroutine TargetSystem first checks if the list has a count > 0 "if (etm.targets.Count > 0)" or else "lockedBlocked = null; StopCoroutine(TargetSystem());" etc.

The issue im having is 3 out of the 4 turrets are passing the if count > 0 and 1 is returning the else = null?!

 public class TurretController : MonoBehaviour
 {
     private EnemyTargetManager etm;
     [HideInInspector] public Transform lockedBlock = null;
     public XRLineRenderer beam1;
     public float fireDistance = 300.0f;
     public float rayDistance = 300.0f;
     public float turnSpeed = 50.0f;
     private Quaternion targetRot;
     private bool targetAcquired = false;
     private ShipBlockColl blockColl;
     private AudioSource source;
     
 
     private void Start()
     {
         etm = FindObjectOfType<EnemyTargetManager>();
         etm = etm.GetComponent<EnemyTargetManager>();
         StartCoroutine(TargetSystem());
         source = GetComponent<AudioSource>();
     }
     
     private void Update()
     {
         if (targetAcquired == true && lockedBlock != null)
         {
             targetRot = Quaternion.LookRotation(lockedBlock.transform.position - transform.position);
             transform.rotation = Quaternion.Slerp(transform.rotation, targetRot, turnSpeed * Time.deltaTime);
         }
     }
     
     IEnumerator TargetSystem()
     {
         //print("target started!");
         
         if (etm.targets.Count > 0)
         {
             //print("found target");
             if (etm.targets[0].CompareTag("ShipBlock"))
             {
                 lockedBlock = etm.targets[Random.Range(0, etm.targets.Count)];
                 Vector3 blockDistance = lockedBlock.position;
                 float dist = Vector3.Distance(transform.position, blockDistance); //Debug.Log(dist);
                 if (Vector3.Distance(transform.position, blockDistance) < fireDistance)
                 {
                     targetAcquired = true;
                     yield return new WaitForSeconds(1f);
                     StartCoroutine(FireBeam());
                     yield return new WaitForSeconds(5f);
                     targetAcquired = false;
                     yield return StartCoroutine(TargetSystem());
                 }
                 else
                 {
                     yield return new WaitForSeconds(1f);
                     StartCoroutine(TargetSystem());
                 }
             }
         }
         
         else
         {                                                            
             lockedBlock = null;                          // <------o but why?
             StopCoroutine(TargetSystem());
             print("LockedBlock Null!");
             yield return null;
         }
         
         if (etm.targets.Count < 0)
         {
             print("No target Count!");
             StopCoroutine(TargetSystem());
             lockedBlock = null;
             yield return null;
         }
     }
 
     IEnumerator FireBeam()
     {
         //print("Beam Fired!");
         source.pitch = 0.9f;
         source.Play();
         yield return new WaitForSeconds(0.80f);
         beam1.enabled = true;
         CastBeam();
         yield return new WaitForSeconds(2.5f);
         source.Stop();
         beam1.enabled = false;
         yield return null;
     }
 
     public void CastBeam()
     {
         RaycastHit hit;
         Vector3 direction = transform.forward;
         LayerMask mask = LayerMask.GetMask("ShipBlock");
         
         if (Physics.Raycast(transform.position, direction, out hit, rayDistance, mask))
         {
             //print("ray fired!");
             ShipBlockColl blockColl = hit.collider.GetComponent<ShipBlockColl>();
             //Debug.DrawRay(transform.position, direction * rayDistance, Color.red, 2f);
             
             if (blockColl != null && hit.collider.CompareTag("ShipBlock"))
             {
                 //print("beam hit!");
                 blockColl.RayBeamHit();
             }
             else
             {
                 Debug.Log("Did not Hit");
             }
         }
     }
 }

I have found a dirty workaround by copying and renaming the script just for this one turret and adding this to the else statement............

 else
         {                                                            
             lockedBlock = null;                          // <------o but why?
             StopCoroutine(TargetSystem());
             print("LockedBlock Null!");
             yield return new WaitForSeconds(2f);
             StartCoroutine(TargetSystem());
         }
 

After the Coroutine is started again it works fine :/

thanks.