[Help] Input system assert when saving rebinds

So I'm using the following code to load input actions on Start and save whenever a binding is rebound. I am using the code from this previous post: https://forum.unity.com/threads/how-to-save-input-action-bindings.799311/. But whenever I rebind a key and SaveKeybinds gets called called I get the following exception



This is also accompanied by failing to load keybinds on start. Heres the code I use:

Code (CSharp):

1.     [SerializeField] InputActionAsset inputAsset;
2.     [SerializeField] List<RebindActionUI> rebindUis;
3.  
4.     void Start()
5.     {
6.         LoadKeybinds();
7.  
8.         foreach (var rebind in rebindUis)
9.             rebind.stopRebindEvent.AddListener(SaveKeybinds);
10.     }
11.  
12.     void SaveKeybinds(RebindActionUI ui, InputActionRebindingExtensions.RebindingOperation opr)
13.     {
14.         var rebinds = inputAsset.ToJson();
15.         PlayerPrefs.SetString("Rebinds", rebinds);
16.     }
17.  
18.     void LoadKeybinds()
19.     {
20.         var rebinds = PlayerPrefs.GetString("Rebinds");
21.  
22.         if (!string.IsNullOrEmpty(rebinds))
23.             inputAsset.LoadFromJson(rebinds);
24.     }

Is this an issue with my setup or is it a Unity issue? Thanks.