Bug Prefab spontaneously loses serialized references

I'm instantiating a prefab that has a few serialize fields that reference components within the same prefab. Without interacting with those fields in any way, they suddenly become null leading to a UnassignedReferenceException. Indeed in the inspector, the references dissapear, even though the prefab still contains the relevant components.



Relevant code:

Code (CSharp):

1.  
2. //HUD.cs
3. ...
4.     public BotInfoTag botTagPrefab;
5.     public Transform botTagPanel;
6. ...
7.     public void AddBotTag() {
8.         Instantiate(botTagPrefab, botTagPanel).Init();
9.     }
10. ...
11.  
12.  
13.  
14. //BotInfoTag.cs
15. using UnityEngine;
16.  
17. /// <summary>
18. /// Tag in UI layer that is used to display info about a given bot.
19. /// </summary>
20. public class BotInfoTag : MonoBehaviour {
21.  
22.     [SerializeField]
23.     private TMPro.TMP_Text playerNameText;
24.     [SerializeField]
25.     private CanvasGroup cg;
26.  
27.     public void Init() {
28.  
29.         //Ugly fix I would prefer to avoid
30.         /*
31.         if(cg == null)
32.             cg = GetComponent<CanvasGroup>();
33.         if (playerNameText == null)
34.             playerNameText = GetComponentInChildren<TMPro.TMP_Text>();
35.         */
36.        
37.         cg.interactable = false; //null reference here, cg is otherwise never referenced
38.         cg.blocksRaycasts = false;
39.         playerNameText.text = "Cool player dude";
40.     }
41. }
42.  

 

Prefabs can never refer to something in a scene, only the other way around. Is this your problem?

The reason: prefabs are files on disk, the scene is ephemeral and only in memory.

 

A bit awkward replying so quickly, but after trying literally everything else, just reimporting the prefab magically fixed it.
Clicking on the prefab in the inspector would show the 2 fields as empty, while opening it showed the fields filled in.