oneOf schema validation fails when relying on nullable property due to json-schema draft version about connexion HOT 3 CLOSED

openapi: "3.0.0"
info:
  version: 1.0.0
  title: something
consumes:
  - application/json
produces:
  - application/json
paths:
  /thing:
    description: Failing
    responses:
      "200":
        description: OK
        content:
          application/json:
            schema:
              oneOf:
                - $ref: "#/definitions/Foo"
                - $ref: "#/definitions/Bar"
definitions:
  Foo:
    title: Foo
    type: object
    properties:
      foo:
        type: string
        nullable: false
  Bar:
    title: Bar
    type: object
    properties:
      bar:
        type: string
        nullable: false