[Question] destroyCancellationToken not preventing access after destruction?

[manuelhuber]

Hello, I'm running into problems with LMotion when destroying GameObjects.
This is my code:

public class FlyingIcon : MonoBehaviour {
    private Vector3 position {
        get => RectTransform.anchoredPosition;
        set => RectTransform.anchoredPosition = value;
    }
    private RectTransform RectTransform {
        get {
            if (!_rectTransform) _rectTransform = GetComponent<RectTransform>();
            return _rectTransform;
        }
    }

    public void DoAnimation() {
        var token = destroyCancellationToken;

        await LMotion.Create(startPosition, upPosition, upDuration)
            .WithEase(Ease.OutCubic)
            .Bind(pos => position = pos)
            .ToUniTask(token);
    }

And it results in this exception

MissingReferenceException: The object of type 'ui.FlyingIcon' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEngine.Object+MarshalledUnityObject.TryThrowEditorNullExceptionObject (UnityEngine.Object unityObj, System.String parameterName) (at <ad78ec25e30a41adb27f06b0ae6b00c9>:0)
UnityEngine.Bindings.ThrowHelper.ThrowNullReferenceException (System.Object obj) (at <ad78ec25e30a41adb27f06b0ae6b00c9>:0)
UnityEngine.Component.GetComponentFastPath (System.Type type) (at <ad78ec25e30a41adb27f06b0ae6b00c9>:0)
UnityEngine.Component.GetComponent[T] () (at <ad78ec25e30a41adb27f06b0ae6b00c9>:0)
ui.FlyingIcon.get_RectTransform () (at Assets/src/ui/FlyingIcon.cs:49)
ui.FlyingIcon.set_position (UnityEngine.Vector3 value) (at Assets/src/ui/FlyingIcon.cs:36)
ui.FlyingIcon+<>c__DisplayClass37_0.<FlyInternal>b__0 (UnityEngine.Vector3 pos) (at Assets/src/ui/FlyingIcon.cs:146)

The exception is thrown in this line
if (!_rectTransform) _rectTransform = GetComponent<RectTransform>();
which is called from line 146 .Bind(pos => position = pos).

Is this expected behaviour?
I'd have thought that the destroyCancellationToken prevents the bind callback from running after the GO/component has been destroyed. Or is there a potential race condition in the frame that the GO is destroyed? If so what is the canonnical way to prevent this? Do I need an additional if(!this) return check inside my Bind callback?

[manuelhuber]

I just did some more debugging: When the exception is thrown !this == true but token.IsCancellationRequested == false. So it seems like the token is lagging behind actual destruction.