Even when 'T' is definite, ScriptableObject.CreateInstance<T>() returns null

So I'm aware that for ScriptableObject.CreateInstance<T> to work, 'T' can't remain generic.
I have the following code, in which 'T' is eventually made definite:

Abstract base class

Code (CSharp):

1.  
2.     public abstract class MouthSetGenericEditor<T> : Editor
3.         {
4.             public static void CreateMouthSet(T fillerResource)
5.             {
6.                 var mouthset = ScriptableObjectUtility.CreateAsset<MouthSetGeneric<T>>();
7.             }
8.         }
9.  

Child class where type is made definite

Code (CSharp):

1.  
2.     [CustomEditor(typeof(MouthSetGeneric<Sprite>))]
3.         public class MouthSetSpriteEditor : MouthSetGenericEditor<Sprite>
4.         {
5.             private static readonly Sprite placeholderSprite = Resources.Load<Sprite>("Placeholder");
6.    
7.             [MenuItem("Assets/Rhubarb/Create Sprite Mouthset")]
8.             public static void CreateSpriteMouthSet()
9.             {
10.                 CreateMouthSet(placeholderSprite);
11.             }
12.         }
13.  

Utility where ScriptableObject.CreateInstance<T>() is called

Code (CSharp):

1.  
2.     public static class ScriptableObjectUtility
3.         {
4.             public static T CreateAsset<T>() where T : ScriptableObject
5.             {
6.                 T asset = ScriptableObject.CreateInstance<T>();
7.    
8.                 if (asset == null)
9.                     Debug.Log("asset null");
10.    
11.                 // more code...
12.              }
13.         }
14.  

In the same block where ScriptableObject.CreateInstance<T>() is called, if I log typeof(T).ToString(), the console outputs MouthSetGeneric`1[UnityEngine.Sprite]. So it looks like type T was made definite, but the ScriptableObject instantiation call isn't behaving as though it is.

Any idea what could be going on? Thanks!