Why my enemy starts to bump between two waypoints during its patrolling

Hello everybody. I attached the following script to an enemy patrolling a maze:

 using UnityEngine;
 using UnityEngine.AI;
 using System.Collections;
 
 
 public class Patrol : MonoBehaviour {
 
     public GameObject[] points;
     private int destPoint = 0;
     private NavMeshAgent agent;
     Animator anim;
     string state = "patrol";
     private Transform play;
     private float distance;
     private bool chasingPlayer = false;
     private float rotSpeed = 1f;
     private float rotSpeedPatrol = 0.7f;
     private float accuracyWP = 0.1f;
 
     void Start () {
         agent = GetComponent<NavMeshAgent>();
         points = GameObject.FindGameObjectsWithTag ("Path");
         anim = GetComponent<Animator> ();
         play = GameObject.FindWithTag("Player").transform;
         // Disabling auto-braking allows for continuous movement
         // between points (ie, the agent doesn't slow down as it
         // approaches a destination point).
         agent.autoBraking = false;
 
         GotoNextPoint();
     }
 
     void GotoNextPoint() {
         // Returns if no points have been set up
         if (points.Length == 0)
             return;
 
         // Set the agent to go to the currently selected destination.
         agent.destination = points[destPoint].transform.position;
 
         // Choose the next point in the array as the destination,
         // cycling to the start if necessary.
         destPoint = (destPoint + 1) % points.Length;
     }
 
 
     void Update () {
         // Choose the next destination point when the agent gets
         // close to the current one.
         Vector3 direction = play.position - this.transform.position;
         distance = Vector3.Distance(play.position, transform.position);
         direction.y = 0;
 
         if (distance >= 9f) {
             state = "patrol";
             chasingPlayer = false;
 
         } else if (distance < 9f ) {
             //head.transform.LookAt(player.position);
             state = "pursuing";
             chasingPlayer = true;
 
         } else if (distance < 8f) {
             state = "pursuing";
             chasingPlayer = true;
 
         }
 
         if(play == null) {
             state = "patrol";
             chasingPlayer = false;
         }
 
         if(chasingPlayer == true) {
             state = "pursuing";
             this.transform.rotation = Quaternion.Slerp(this.transform.rotation,
                 Quaternion.LookRotation(direction), rotSpeed * Time.deltaTime);
 
             if(direction.magnitude > 5f) {
                 agent.SetDestination(play.position);
                 agent.speed = 8f;
                 anim.SetBool("isAttacking", false);
                 anim.SetBool("isWalking", true);
                 anim.SetBool("isIdle", false);
             } else {
                 agent.speed = 0f;
                 anim.SetBool ("isAttacking", true);
                 anim.SetBool("isWalking", false);
                 anim.SetBool("isIdle", false);
             }
 
         } else if(chasingPlayer == false) {
 
             agent.speed = 2.25f;
 
             if(state == "patrol" && points.Length > 0) {
                 
                 anim.SetBool("isIdle",false);
                 anim.SetBool("isWalking",true);
                 anim.SetBool("isAttacking",false);
 
                 if(Vector3.Distance(points[destPoint].transform.position, transform.position) < accuracyWP)
                 {
 
                     destPoint++;
                     if(destPoint >= points.Length)
                     {
                         destPoint = 0;
                     }    
                 }
 
                 //rotate towards waypoint
                 direction = points[destPoint].transform.position - transform.position;
 
                 if(agent.remainingDistance < 0.2f)
                 {
                     WaitAndGo();
                 }
             }
 
             this.transform.rotation = Quaternion.Slerp(transform.rotation,
                 Quaternion.LookRotation(direction), rotSpeedPatrol * Time.deltaTime);
         }
     }
 
     void WaitAndGo() {
         GotoNextPoint ();
     }
 }
 

I don't understand why, but at a certain point my enemy starts to walk between two waypoints, ignoring the remaining ones. Any suggestions?