Failed validating 'oneOf'

No files, tests, or entry points are named. Start by reproducing the supplied validation error with the OpenAPI instance, then trace validation of the callbacks property and its oneOf schemas. Done means identifying whether the reported structure is invalid or the validator is producing an incorrect diagnostic, with a focused regression test if a defect is confirmed.

Hello,
I don't understand the following validation error:

{'{$response.header.Location}': {'get': {'requestBody': {}, 'responses': {'301': {'x-scope': ['', '#/components/callbacks/moveProgress'], '$ref': '#/components/responses/MoveProgress'}, '303': {'x-scope': ['', '#/components/callbacks/moveProgress'], '$ref': '#/components/responses/MoveSuccess'}}}}} is not valid under any of the given schemas

Failed validating 'oneOf' in schema['properties']['paths']['patternProperties']['^/']['properties']['put']['properties']['callbacks']['additionalProperties']:
    {'oneOf': [{'$ref': '#/definitions/callback'},
               {'$ref': '#/definitions/reference'}]}

On instance['paths']['/users/user/{dn}']['put']['callbacks']['move-progress']:
    {'{$response.header.Location}': {'get': {'requestBody': {},
                                             'responses': {'301': {'$ref': '#/components/responses/MoveProgress',
                                                                   'x-scope': ['',
                                                                               '#/components/callbacks/moveProgress']},
                                                           '303': {'$ref': '#/components/responses/MoveSuccess',
                                                                   'x-scope': ['',
                                                                               '#/components/callbacks/moveProgress']}}}}}

The x-scope was not added by myself. I don't have any oneOf defined.
Maybe someone can point me to the error?