Unity Crashes From While Loop and Can't fix

I was creating the following state machine for a Uni project and for some reason I can't figure out the solution to the crashing. I know it is being caused by the while loop within each (eg lines 107-131) of the State IEnumerators but can't put my finger on it exactly. Help is greatly appreciated, thanks in advance.

 using UnityEngine;
 using System;
 using System.Collections;
 using System.Collections.Generic;
 
 [RequireComponent(typeof(Flock))]
 public class PreyStateMachine : Life
 {
     #region Variables
     public enum PreyStates
     {
         Flock,
         Wander,
         Evade,
         Hide,
     }
 
     [Header("Prey Variables")]
     public bool useHurtColor = true;
     public Color hurtColor = Color.red;
 
     [Header("State Machine Variables")]
     public PreyStates preyState;
 
     [Header("Timer Values")]
     public float waitTime;
     private float timer;
 
     [Header("Behaviour Objects")]
     [SerializeField] private FlockBehaviour FlockBehaviour;
     [SerializeField] private FlockBehaviour WanderBehaviour;
     [SerializeField] private FlockBehaviour EvadeBehaviour;
     [SerializeField] private FlockBehaviour HideBehaviour;
     #endregion
 
     #region Default
     protected override void Start()
     {
         base.Start();
 
         #region Debugging
         if (GetComponent<Flock>() != null && flock == null)
         {
             flock = GetComponent<Flock>();
         }
 
         if (flock == null)
         {
             Debug.LogError("Prey State Machine couldnt find flock");
         }
         #endregion
 
         ChangeStateTo(preyState.ToString());
 
     }
 
     void Update()
     {
         stateDisplay.text = preyState.ToString();
 
         if (timer < -1)
         {
             timer -= Time.deltaTime;
         }
     }
     #endregion
 
     #region Prey Functionality
     public void TakeDamage(float damage)
     {
         health -= damage;
     }
 
     public void PlayHurtColorEffectVoid(SpriteRenderer renderer, int repeatAmount, float waitTime)
     {
         PlayHurtColorEffect(renderer, repeatAmount, waitTime);
     }
 
 
     public IEnumerator PlayHurtColorEffect(SpriteRenderer renderer, int repeatAmount, float waitTime)
     {
         Color tempStartColor = renderer.color;
 
         for (int i = 0; i < repeatAmount; i++)
         {
             renderer.color = hurtColor;
             yield return new WaitForSeconds(waitTime);
             renderer.color = tempStartColor;
         }
     }
     #endregion
 
     #region State Machine Functionality
     ///
 
     #region Flock
     public IEnumerator FlockState()
     {
         Debug.Log("Flock: ENTER");
 
         preyState = PreyStates.Flock;
         flock.behaviour = FlockBehaviour;
 
         //StartCoroutine("DelayStateChangeFW");
         timer = waitTime;
 
         while (preyState == PreyStates.Flock)
         {
             foreach (FlockAgent agent in flock.agents)
             {
                 List<Transform> filteredContext = (contextFilter == null) ? flock.areaContext : contextFilter.Filter(agent, flock.areaContext);
 
                 if (filteredContext.Count > 0)
                 {
                     //StopCoroutine("DelayStateChangeFW");
                     timer = -10;
                     ChangeStateTo("Evade");
                     preyState = PreyStates.Evade;
                     yield return null;
                 }
             }
 
             if (timer >= 0)
             {
                 ChangeStateTo("Wander");
                 preyState = PreyStates.Wander;
                 yield return null;
             }
 
             yield return null;
         }
 
         Debug.Log("Flock: EXIT");
     }
     #endregion
 
     #region Wander
     public IEnumerator WanderState()
     {
         Debug.Log("Wander: ENTER");
 
         preyState = PreyStates.Wander;
         flock.behaviour = WanderBehaviour;
 
         //StartCoroutine("DelayStateChangeFW");
         timer = waitTime;
 
         while (preyState == PreyStates.Wander)
         {
             foreach (FlockAgent agent in flock.agents)
             {
                 List<Transform> filteredContext = (contextFilter == null) ? flock.areaContext : contextFilter.Filter(agent, flock.areaContext);
 
                 if (filteredContext.Count > 0)
                 {
                     //StopCoroutine("DelayStateChangeFW");
                     timer = -10;
                     ChangeStateTo("Evade");
                     preyState = PreyStates.Evade;
                     yield return null;
                 }
             }
 
             if (timer >= 0)
             {
                 ChangeStateTo("Flock");
                 preyState = PreyStates.Flock;
                 yield return null;
             }
 
             yield return null;
         }
 
         Debug.Log("Wander: EXIT");
     }
     #endregion
 
     #region Evade
     public IEnumerator EvadeState()
     {
         Debug.Log("Evade: ENTER");
 
         preyState = PreyStates.Evade;
         flock.behaviour = EvadeBehaviour;
 
         //StartCoroutine("DelayStateChangeEH");
         timer = waitTime;
 
         while (preyState == PreyStates.Evade)
         {
             foreach (FlockAgent agent in flock.agents)
             {
                 List<Transform> filteredContext = (contextFilter == null) ? flock.areaContext : contextFilter.Filter(agent, flock.areaContext);
 
                 if (filteredContext.Count <= 0)
                 {
                     //StopCoroutine("DelayStateChangeEH");
                     timer = -10;
                     ChangeStateTo("Flock");
                     preyState = PreyStates.Flock;
                     yield return null;
                 }
             }
 
             if (timer >= 0)
             {
                 ChangeStateTo("Hide");
                 preyState = PreyStates.Hide;
                 yield return null;
             }
 
             yield return null;
         }
 
         Debug.Log("Evade: EXIT");
     }
     #endregion
 
     #region Hide
     public IEnumerator HideState()
     {
         Debug.Log("Hide: ENTER");
 
         preyState = PreyStates.Hide;
         flock.behaviour = HideBehaviour;
 
         //StartCoroutine("DelayStateChangeEH");
         timer = waitTime;
 
         while (preyState == PreyStates.Hide)
         {
             foreach (FlockAgent agent in flock.agents)
             {
                 List<Transform> filteredContext = (contextFilter == null) ? flock.areaContext : contextFilter.Filter(agent, flock.areaContext);
 
                 if (filteredContext.Count <= 0)
                 {
                     //StopCoroutine("DelayStateChangeEH");
                     timer = -10;
                     ChangeStateTo("Flock");
                     preyState = PreyStates.Flock;
                     yield return null;
                 }
             }
 
             if (timer >= 0)
             {
                 ChangeStateTo("Evade");
                 preyState = PreyStates.Evade;
                 yield return null;
             }
 
             yield return null;
         }
 
         Debug.Log("Evade: EXIT");
     }
     #endregion
 
     #region State Changing
     void ChangeStateTo(string methodName)
     {
         StartCoroutine(methodName + "State"); //change the state to the passed value plus "State"
     }
 
     /*public IEnumerator DelayStateChangeFW()
     {
         Debug.Log("Counting...");
 
         yield return new WaitForSeconds(10);
 
         if (preyState == PreyStates.Flock)
         {
             ChangeStateTo("Wander");
             //yield return null;
         }
         else
         {
             ChangeStateTo("Flock");
         }
     }
 
     public IEnumerator DelayStateChangeEH()
     {
         Debug.Log("Counting...");
 
         yield return new WaitForSeconds(10);
 
         if (preyState == PreyStates.Evade)
         {
             ChangeStateTo("Hide");
         }
         else
         {
             ChangeStateTo("Evade");
         }
     }*/
     #endregion
     #endregion
 }