API Gateway/OpenAPI 3.0 deploy warning, what is ComposedSchema?

Hello all! I am trying to use the allOf keyword to inherit attributes of one schema model into another as such:

providerIdentityExpansion:
      description: ID of the Provider Identity with fields possibly expanded.
      allOf:
        - $ref: '#/components/schemas/providerIdentityNoExpansion'
      properties:
        oft_confused_with:
          oneOf:
          - $ref: '#/components/schemas/oft_confused_with'
          - $ref: '#/components/schemas/oftConfusedWithExpansionArray'

      title: ProviderIdentityExpansion
      type: object

I previously just duplicated the model, but changed the names (one with expansion, one without). But using allOf, when I use swagger-cli to bundle all OpenAPI 3.0 Spec docs together into one file and deploy on API Gateway, it responds with following warning:

"Unsupported model type 'ComposedSchema' in 200 response to method 'GET /providers/{id}/identity'. Ignoring.",
        "Unsupported model type 'ComposedSchema' in 200 response to method 'GET /providers/{id}/identity/children'. Ignoring."

Is anyone familiar with the model type ComposedSchema, and how to utilize the allOf keyword without triggering this error in AWS?