Enabling a hidden GameObject with a MeshRenderer - makes it visible in previews.

I'd like to confirm this is a bug, and not something I am doing wrong.

Given the monobehavior below:

If I click in its inspector - createItHidden , then click createItNow, then disable, and renable this monobehavor object:

The created object is visible, not only in the scene, but ALSO in the project's icons, an inspectors preview's (materials, models)

 [ExecuteInEditMode]
 public class HiddenObjectCreator : MonoBehaviour {
 
     public GameObject hiddenObject;
     public bool createItNow = false;
     public bool createItHidden = false;
 
 
 
     private void OnEnable()
     {
         if(hiddenObject)
             hiddenObject.SetActive(true);
     }
 
     private void OnDisable()
     {
         if (hiddenObject)
             hiddenObject.SetActive(false);
     }
     // Update is called once per frame
     void Update ()
     {
         if (createItNow)
         {
             createItNow = false;
             hiddenObject = GameObject.CreatePrimitive(PrimitiveType.Cube);
             hiddenObject.transform.localScale = new Vector3(.1f, 2, .1f);
             if (createItHidden)
                 hiddenObject.hideFlags = HideFlags.HideAndDontSave;
         }
     }
 }