pubblic variable don't get change from script with OnTriggerStay

Hi everyone i am having some trouble with my scripts communication the script i link should change a variable in an other script when the player stay for 2 second on a platform everything work and no error but the variable that should get change never really change so everything outside the script doesn't work any idea why ? this is the two script first the one that should change the var on the other script called Platform the tochingPlatform variables is set in editor for every platform that has the script attached

thanks for the help i am going crazy everything work no error but can't find the logic that doesn't change the variable

List item

 using UnityEngine;
 using System.Collections;
 
 public class ShiStayRespawn : MonoBehaviour {
 
     public int touchingPlatform;
     
     public GameObject respawnController;
     public CheckPoint checkPoint;
     
 
 
     // Use this for initialization
     void Start () {
 
         respawnController = GameObject.Find("RespawnController");
         checkPoint = respawnController.GetComponent<CheckPoint>();
     
     
     }
 
     void OnTriggerEnter(Collider col)
     {
         
         checkPoint.starTimer = Time.time;
         checkPoint.nextTimer = checkPoint.starTimer + 2;
     }
 
     void OnTriggerStay(Collider col)
     {
         if(col.gameObject.CompareTag("Player"))
         {
             
             checkPoint.starTimer = Time.time;
             if (checkPoint.starTimer >= checkPoint.nextTimer && touchingPlatform == 0)
             {
                 Debug.Log("Start");
                 checkPoint.Platform = 0;
                 Debug.Log("Last Check : " + checkPoint.lastCheckPoint.ToString() + "Touchin " + touchingPlatform.ToString());
             }
             if (checkPoint.starTimer >= checkPoint.nextTimer && touchingPlatform == 1)
             {
                 Debug.Log("1");
                 checkPoint.Platform = 1;
                 checkPoint.saveState = 2;
                 Debug.Log("Last Check 2222222 : " + checkPoint.lastCheckPoint.ToString() + "Touchin " + touchingPlatform.ToString());
                 
             }
             if (checkPoint.starTimer >= checkPoint.nextTimer && touchingPlatform == 2)
             {
                 Debug.Log("End");
                 //checkPoint.lastCheckPoint = checkPoint.checkPoints[2].transform.position;
                 checkPoint.Platform = 2;
                 checkPoint.saveState = 3;
                 Debug.Log("Last Check 3333333 : " + checkPoint.lastCheckPoint.ToString() + "Touchin " + touchingPlatform.ToString());
                 
             }
         }
     }
 
     public void OnTriggerExit(Collider other)
     {
         Debug.Log(checkPoint.lastCheckPoint.ToString());
         //checkPoint.Platform = touchingPlatform;
     }
 
 
 
 
 
 }

and this is the script that should received the change value

 using UnityEngine;
 using System.Collections;
 
 public class CheckPoint : MonoBehaviour {
 
     public Vector3 lastCheckPoint ;
     public int saveState;
     public float starTimer;
     public float nextTimer;
     public GameObject[] checkPoints = new GameObject[3];
     
     public  GameObject[] lightsPlatform = new GameObject[5];
 
     public  int Platform = 0;
     
 
     // Use this for initialization
     void Start () 
     {
         checkPoints[0] = GameObject.Find("TheStart");
         checkPoints[1] = GameObject.Find("Check1");
         checkPoints[2] = GameObject.Find("TheEnd");
 
 
         saveState = 1;
         
         AssignCheckPoint(Platform);
     }
 
     void Update()
     {
         AssignCheckPoint(Platform);
         
     }
 
     public void AssignCheckPoint(int other)
     {
         lastCheckPoint = checkPoints[other].transform.position;
     }
     
 
 }