DatasetV2 Owned typing failure

[abulte]

The DatasetV2 type is not compatible with Owned, even though it is composed with it.

See the example fiddle. I would expect dataset to be compatible with the signature of useMyComposable but there's the following error:

Argument of type 'DatasetV2' is not assignable to parameter of type 'Owned'.
  Type 'DatasetV2' is not assignable to type '{ organization: null; owner: User; }'.
    Types of property 'organization' are incompatible.
      Type 'Organization | null' is not assignable to type 'null'.
        Type 'Organization' is not assignable to type 'null'.

For reference, a Owned like this would work (but less smart):

interface Owned {
  organization?: Organization | null;
  owner?: User | null;
}