Error from declaring List within ScriptableObject

My scriptable object:

 [CreateAssetMenu(fileName = "AudioCollection", menuName = "AudioCollection")]
 public class AudioClipCollection : ScriptableObject {
     
         [System.Serializable]
         public class Clip{
             public string name;
             public AudioClip audioClip;
         }
     
         public List<Clip> clips = new List<Clip>();
     }

The list declaration line gives the error:

     AudioClipCollection must be instantiated using the ScriptableObject.CreateInstance method
 instead of new AudioClipCollection.

How am I meant to be declaring lists within a scriptable object? I have used 'ScriptableObject.CreateInstance' to create the scriptable object, so that is not the issue.

Cheers!