Start function works on game startup but gives argument out of range error on scene reload

Hello everyone, I am relatively new to unity and am working on a mobile game. I have created a random level generator script which allows me to create infinite random levels using a combination of platform prefabs. In theory, this code would allow me to create the whole game using one scene which I would reload on level completion. The code works fine when I start the game in the editor, however, when I reload the scene using UnityEngine.SceneManagement, I get an argument out of range exception on line 40. I don't know what is causing the error. Please help...

Code (CSharp):

1. public GameObject startPlat, endPlat, heelPlat, heelPlat2, sandPlat, sandPlat2, waterPlat, jogPlat, jogPlat2;
2.     public GameObject playerPlat, enemyPlat;
3.     public List<GameObject> platPartList, currentParts;
4.     public int levelLength;
5.     PlayerNew player;
6.     float zOffset;
7.     GameObject prevPart;
8.     UIManagerNew uimanNew;
9.  
10.     // Start is called before the first frame update
11.     void OnEnable()
12.     {
13.         uimanNew = FindObjectOfType<UIManagerNew>().GetComponent<UIManagerNew>();
14.         if (uimanNew.makeLevel)
15.         {
16.             levelLength = PlayerPrefs.GetInt("currentLvlLength");
17.             player = FindObjectOfType<PlayerNew>().GetComponent<PlayerNew>();
18.             if (player.heel)
19.             {
20.                 platPartList.Add(heelPlat);
21.                 platPartList.Add(heelPlat2);
22.             }
23.             if (player.sand)
24.             {
25.                 platPartList.Add(sandPlat);
26.                 platPartList.Add(sandPlat2);
27.             }
28.             if (player.water)
29.                 platPartList.Add(waterPlat);
30.             if (player.jog)
31.             {
32.                 platPartList.Add(jogPlat);
33.                 platPartList.Add(jogPlat2);
34.             }
35.             GameObject temp = Instantiate(startPlat, new Vector3(0f, 0f, zOffset), startPlat.transform.rotation);
36.             temp.transform.SetParent(playerPlat.transform);
37.             zOffset += 7.5f;
38.             for (int i = 0; currentParts.Count < levelLength; i++)
39.             {
40.                 int rand = Random.Range(0, platPartList.Count);
41.                 //Debug.Log(platPartList.Count);
42.                 temp = platPartList[rand];
43.                 if (temp != prevPart)
44.                 {
45.                     GameObject temp2 = Instantiate(temp, new Vector3(0f, 0f, zOffset), startPlat.transform.rotation);
46.                     temp2.transform.SetParent(playerPlat.transform);
47.                     zOffset += 7.5f;
48.                     currentParts.Add(temp2);
49.                     prevPart = temp;
50.                 }
51.             }
52.             temp = Instantiate(endPlat, new Vector3(0f, 0f, zOffset), endPlat.transform.rotation);
53.             temp.transform.SetParent(playerPlat.transform);
54.             temp = Instantiate(playerPlat, new Vector3(-3f, 0f, 0f), Quaternion.identity);
55.             temp.transform.SetParent(enemyPlat.transform);
56.  
57.         }
58.  
59.     }

 

Sorry guys, false Alarm. I found the solution. What happened was that I had multiple start functions on multiple scripts. My concept required them to execute in a certain order (which they didn't!!). I found out the handy "Script Execution Order" setting in unity Player Settings which solved my problem.