Unity StopCoroutine doesn't work at all in nested Coroutine but it is ambiguous

DamnUnityCoroutine.cs

using System.Collections;
using Sirenix.OdinInspector;
using UnityEngine;

public class DamnUnityCoroutine : MonoBehaviour {
    private Coroutine coroutine;

    [Button(ButtonSizes.Large)]
    public void Go() {
        coroutine = StartCoroutine(A());
    }

    [Button(ButtonSizes.Large)]
    public void Stop() {
        if (coroutine != null) {
            StopCoroutine(coroutine);
        }
    }

    private IEnumerator A() {
        while (true) {
            yield return B();
        }
    }

    public IEnumerator B() {
        while (true) {
            yield return C();
        }
    }


    private IEnumerator C() {
        // if line a is alive: StopCoroutine doesn't work
        // if line b is alive: StopCoroutine works 

        // line `a`
        yield return D();
        // line `b`
        yield return null;
        print($"{Time.time}");
    }

    private IEnumerator D() {
        yield return null;
    }
}

https://stackoverflow.com/questions/51550499/unity-stopcoroutine-does-not-stop-coroutines-when-there-are-multi-layer-or-nest/51553311#comment90138504_51563210

https://issuetracker.unity3d.com/issues/coroutine-cant-be-stopped-via-stopcoroutine-if-it-has-3-or-more-nested-yield-return-coroutines