Problem with LIST of Gameobjects when running

I'm doing a paltform prefab for easy editing, and i've tried instantiating some "pathwaypoints" as gameobjects while still in the editor.
The problem is: I add this GO to a list in my gamemanager, and they are added correctly, but as soon as I press Play those points are deleted from the list and become null. ¿What am i doing wrong?

Heres my code:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. //using UnityEditor;
5. using UnityEngine.SceneManagement;
6.  
7.  
8. public enum PlatformUnit { Fija =0, Flexible, Columpio}
9. public enum PlatformUnitNormalType { ConActivacion=0,SinActivacion }
10. public enum PlatformUnitNormalTypeOfMovement { Bucle = 0, dePuntoaPunto, BucleCerrado }
11. [System.Serializable]
12. public class PlatformType
13. {
14.     //Types to choose
15.     public PlatformUnit unit;
16.     public PlatformUnitNormalType unitNT;
17.     public PlatformUnitNormalTypeOfMovement unitNTM;
18.     public PlatformUnit savedunit;
19.  
20.     //General Variables
21.     public float ReactionTime=1f;
22.     public GameObject Trigger;
23.     public float Speed;
24.     public bool TriggerisStatic;
25.  
26.     //Swing variables
27.     public GameObject ConnectedPlatform=null;
28.     public bool isUP=true; //Definido por la position del objeto de ruta
29.     public float FloorDistance=2;
30.  
31.     //Normal Variables
32.    
33.     public int PathwayPoints=1;
34.  
35. }
36. // addrelativeforce , para que la plataforma arrastre al jugador
37.  
38. public class Platform_Script : MonoBehaviour {
39.  
40.     public PlatformType platform;
41.     Platform_Script conPlat;
42.     GameObject Platform_Waypoint;
43.     GameObject Platform_Mesh=null;
44.     public bool triggered = false;
45.     float Lastime=0;
46.     Vector3 Endpos, Startpos;
47.     int PathP,direction=1;
48.  
49.     private void CreateWaypoint(Vector3 position)
50.     {
51.         Platform_Waypoint = Instantiate(Resources.Load("Platforms/Platform_Waypoint") as GameObject, this.transform);
52.         Platform_Waypoint.name = "Platform_Waypoint";
53.         Platform_Waypoint.transform.localPosition = position;
54.         GameManager_lara.gameM.Waypoints.Add(Platform_Waypoint);
55.         //platform.Waypoints.Add(Platform_Waypoint);
56.         //GameObject instance2 = Instantiate(block, obj2.transform.position + (transform.forward * 1.5f), obj.transform.rotation);
57.     }
58.  
59.     private void DestroyWaypoints()
60.     {
61.         foreach(GameObject point in GameManager_lara.gameM.Waypoints)
62.         {
63.             if(point != this.gameObject) DestroyImmediate(point);
64.         }
65.         GameManager_lara.gameM.Waypoints.Clear();
66.     }
67.  
68.  
69.     void AddWaypoints()
70.     {
71.         GameManager_lara.gameM.Waypoints.Add(this.gameObject);
72.         for (int i = 1; i <= platform.PathwayPoints; i++)
73.         {
74.             CreateWaypoint(new Vector3(0, i, 0));
75.         }
76.     }
77.  
78.  
79.     private void OnDrawGizmos()
80.     {
81.  
82.         if (Application.isPlaying == false)
83.         {
84.             if (Platform_Mesh == null) Platform_Mesh = transform.Find("Platform_Mesh").gameObject;
85.  
86.  
87.             //When changing Types
88.             if (platform.savedunit != platform.unit)
89.             {
90.                 switch (platform.unit)
91.                 {
92.                     case PlatformUnit.Columpio:
93.                         DestroyWaypoints();
94.                         CreateWaypoint(new Vector3(0, 0, 0));
95.                         break;
96.                     case PlatformUnit.Flexible:
97.                         DestroyWaypoints();
98.                         AddWaypoints();
99.                         break;
100.                     case PlatformUnit.Fija:
101.                         DestroyWaypoints();
102.                         break;
103.                 }
104.                 platform.savedunit = platform.unit;
105.             }
106.  
107.  
108.             //When changing options
109.             if (platform.unit == PlatformUnit.Columpio)
110.             {
111.                 Platform_Waypoint = transform.Find("Platform_Waypoint").gameObject;
112.                 platform.Trigger = transform.Find("Platform_Trigger").gameObject;
113.                 if (platform.isUP) { Platform_Waypoint.transform.localPosition = new Vector3(0, -platform.FloorDistance, 0); Platform_Mesh.transform.localPosition = new Vector3(0, 0, 0); if (!platform.TriggerisStatic) platform.Trigger.transform.localPosition = new Vector3(0, 0, 0); }
114.                 else { Platform_Waypoint.transform.localPosition = new Vector3(0, 0, 0); Platform_Mesh.transform.localPosition = new Vector3(0, -platform.FloorDistance, 0); if (!platform.TriggerisStatic) platform.Trigger.transform.localPosition = new Vector3(0, -platform.FloorDistance, 0); }
115.  
116.             }
117.             if (platform.unit == PlatformUnit.Flexible)
118.             {
119.                 int count = (GameManager_lara.gameM.Waypoints.Capacity - 1);
120.                 if (platform.PathwayPoints != count )
121.                 { DestroyWaypoints(); AddWaypoints(); }
122.             }
123.         }
124.     }
125.  
126.     List<GameObject> Waypnts;
127.  
128.     void Start()
129.     {
130.         platform.Trigger = transform.Find("Platform_Trigger").gameObject;
131.         Platform_Mesh = transform.Find("Platform_Mesh").gameObject;
132.         if (platform.unit == PlatformUnit.Columpio) conPlat = platform.ConnectedPlatform.GetComponent<Platform_Script>();
133.         if (platform.unitNT == PlatformUnitNormalType.SinActivacion) triggered = true;
134.         Waypnts = GameManager_lara.gameM.Waypoints;
135.     }
136.  
137.     private void Update()
138.     {
139.         if (triggered) {
140.             switch (platform.unit)
141.             {
142.                 case PlatformUnit.Columpio:
143.                      MoveColumpio();
144.                     break;
145.                 case PlatformUnit.Flexible:
146.                     MoveFlexible();
147.                     break;
148.                 case PlatformUnit.Fija:
149.                     break;
150.             }
151.         }
152.     }
153.  
154.     private void OnTriggerEnter(Collider other)
155.     {
156.         if (other.tag == "Player" && !triggered && platform.isUP) {
157.             if (platform.unit == PlatformUnit.Columpio)
158.                 { triggered = true; conPlat.triggered = true; }
159.             if (platform.unit == PlatformUnit.Flexible)
160.                 { triggered = true;  PathP = 0; Endpos = Waypnts[PathP].transform.position; }
161.         }
162.     }
163.     private void OnTriggerStay(Collider other)
164.     {
165.         if (platform.unit == PlatformUnit.Columpio)
166.             if (other.tag == "Player" && !platform.isUP && !triggered) SceneManager.LoadScene(SceneManager.GetActiveScene().name);
167.     }
168.  
169.     private void MoveColumpio()
170.     {
171.         if (Lastime == 0) Lastime = Time.time;
172.         float dif = Time.time - Lastime;
173.         if (dif > platform.ReactionTime)
174.         {
175.             if (platform.isUP)
176.             {
177.                 if (Platform_Mesh.transform.localPosition != new Vector3(0,-platform.FloorDistance, 0))
178.                 { Platform_Mesh.transform.localPosition = Vector3.MoveTowards(Platform_Mesh.transform.localPosition, new Vector3(0, -platform.FloorDistance, 0), platform.Speed * Time.deltaTime); }
179.                 else
180.                 {
181.                     platform.isUP = false;
182.                     triggered = false;
183.                     Platform_Waypoint.transform.localPosition = new Vector3(0, 0, 0);
184.                     Lastime = 0;
185.                 }
186.             }
187.             else
188.             {
189.                 if (Platform_Mesh.transform.localPosition != new Vector3(0, 0, 0))
190.                 { Platform_Mesh.transform.localPosition = Vector3.MoveTowards(Platform_Mesh.transform.localPosition, new Vector3(0, 0, 0), platform.Speed * Time.deltaTime); }
191.                 else
192.                 {
193.                     platform.isUP = true;
194.                     triggered = false;
195.                     Platform_Waypoint.transform.localPosition = new Vector3(0,-platform.FloorDistance, 0);
196.                     Lastime = 0;
197.                 }
198.             }
199.             if(!platform.TriggerisStatic) platform.Trigger.transform.position = Platform_Mesh.transform.position;
200.         }
201.     }
202.  
203.     private void MoveFlexible()
204.     {
205.         Vector3 platpos = Platform_Mesh.transform.position;
206.  
207.         //Movimiento
208.         if (platpos != Endpos)
209.         {
210.             Vector3 newpos = Vector3.MoveTowards(Startpos, Endpos, platform.Speed * Time.deltaTime);
211.             Platform_Mesh.transform.position = newpos;
212.             /*Vector3 currentpos = Vector3.Lerp(Startpos, Endpos, Mathf.Cos(Time.time / platform.Speed * Mathf.PI * 2) * -5f + .5f);
213.             Rigidbody rb = Platform_Mesh.GetComponent<Rigidbody>();
214.             rb.MovePosition(currentpos);*/
215.  
216.         }
217.         else
218.         {
219.             Startpos = platpos;
220.             PathP= PathP+ (1*direction);
221.             Endpos = Waypnts[PathP].transform.position;
222.         }
223.  
224.         switch (platform.unitNTM)
225.         {
226.             case PlatformUnitNormalTypeOfMovement.Bucle:
227.                 if (PathP >= Waypnts.Capacity) direction = -1;
228.                 if (direction == -1 && PathP == 0) direction = 1;
229.                 break;
230.             case PlatformUnitNormalTypeOfMovement.BucleCerrado:
231.                 if (PathP >= Waypnts.Capacity) PathP = 0;
232.                 break;
233.             case PlatformUnitNormalTypeOfMovement.dePuntoaPunto:
234.                 if (PathP >= Waypnts.Capacity) { triggered = false; direction = -1; }
235.                 if (direction == -1 && PathP == 0) { triggered = false; direction = 1; }
236.                 break;
237.         }
238.     }
239. }

 

I'm assuming Waypnts is the list?
In Start, you're replacing it with GameManager_lara.gameM.Waypoints, which is going to overwrite anything you had in there before.

 

The list is in the game manager and it's
GameManager_lara.gameM.Waypoints
What i'm doing is only copying that list onto another one in that script when pressing play (so i dont have to keep writing all that long code).

The problems is that only those waypoints (wich are instanced prefabs) are "deleted" from the list, if i add another item to the list wich is not instanced in the scene, it stays.
And when i check the GO list in the gamemanager Inspector (nothing to do with the list in the script), they dissapear anyways when pressing play.