ReDoc shows warning for valid OpenAPI file

[Glurz]

Describe the bug

When generating a ReDoc documentation for a very simple, valid OpenAPI YAML file (given below), ReDoc shows the following warning:

Warning: No "type" specified at "/paths/~1poc~1users~1{userId}~1tokens~1fido~1credentials~1/get/parameters/0". Automatically detected: "object"

What version of ReDoc is built into your gradle plugin? Is it maybe too old to handle openapi 3.0.3?
I'm using org.hidetake.swagger.generator 2.18.2 and io.swagger.codegen.v3:swagger-codegen-cli:3.0.23

To Reproduce:

Generate the ReDoc documentation for the YAML below:

openapi: 3.0.3
info:
  title: FIDO Credentials OpenAPI PoC
  version: 1.2.3
paths:
  '/poc/users/{userId}/tokens/fido/credentials/':
    get:
      operationId: listFidoCredentials
      tags:
        - fidoPoc
      summary: Retrieves all of a user's FIDO credentials.
      description: A longer description of this endpoint.
      parameters:
        - name: userId
          description: The ID of the user.
          in: path
          required: true
          schema:
            type: string
      responses:
        '204':
          description: The list of FIDO credentials of the specified user.

Expected behavior:
The rendered ReDoc does not show warnings.
The problem does not occur if I build the documentation with a stand-alone version of ReDoc (0.10.1).

Environment

Plugin version: 2.18.2
Swagger Codegen version: 3.0.23
Gradle version: 6.7
Java version: 11
OS: macOS