NEED HELP PLEASE: When i kill a one of the three limited "mobSpawned" the "while (true)" don't work and don't spawn a new object. Anyone have a solution for this. Thanks.

 using UnityEngine;
 using System.Collections;
 
 public class SpawnManager : MonoBehaviour
 {
     public GameObject mobPrefabs;
     public Vector3 spawnValues;
     public int mobCount;
     public int mobSpawned;
     public float spawnWait;
     public float startWait;
     public float waveWait;
 
     void Start ()
     {
         StartCoroutine (SpawnWaves ());
     }
         
     IEnumerator SpawnWaves ()
     {
         yield return new WaitForSeconds (startWait);
         while (true)
         {
             for (int i = 0; i < mobCount; i++)
             {
                 Vector3 spawnPosition = new Vector3 (Random.Range (-spawnValues.x, spawnValues.x), spawnValues.y, spawnValues.z);
                 Quaternion spawnRotation = Quaternion.identity;
                 Instantiate (mobPrefabs, spawnPosition, spawnRotation);
                 yield return new WaitForSeconds (spawnWait);
                 mobSpawned++;
 
                 if (mobSpawned <= 2)
                 {
                     yield return (true);
                 }
 
                 if (mobSpawned == 3)
                 {
                     yield break;
                 }
             }
             yield return new WaitForSeconds (waveWait);
         }
     }
 }