openapi-generator issue

openapi-generator-date-models.yaml

openapi: 3.0.0
info:
  title: Dates
  description: Date schemas
  version: 0.0.1
servers:
  - url: /dates
tags:
  - name: Dates
    description: Dates
paths:
  /:
    get:
      summary: Get dates
      description: Get dates
      operationId: getDates
      responses:
        "200":
          description: OK.
          content:
            "*/*":
              schema:
                $ref: "#/components/schemas/dates"
      tags:
        - Dates
components:
  schemas:
    dates:
      title: Dates
      type: object
      properties:
        date:
          $ref: '#/components/schemas/date'
        roDate:
          $ref: '#/components/schemas/readOnlyDate'
        timestamp:
          $ref: '#/components/schemas/timestamp'
        roTimestamp:
          $ref: '#/components/schemas/readOnlyTimestamp'

    date:
      title: Date
      description: >-
        A date, formatted in [RFC 3339](https://tools.ietf.org/html/rfc3339) `date`
        format: `YYYY-MM-DD`.
      type: string
      format: date
      example: 2021-10-31
      minLength: 10
      maxLength: 10
      x-apiture-since: 1.18.0

    readOnlyDate:
      title: Read-Only Date
      description: >-
        A readonly or derived date, formatted in [RFC 3339](https://tools.ietf.org/html/rfc3339) `date`
        format: `YYYY-MM-DD`.
      allOf:
        - $ref: '#/components/schemas/date'
      readOnly: true
      x-apiture-since: 1.18.0

    timestamp:
      title: Timestamp
      description: >-
        A timestamp (an instant in time) formatted in [RFC 3339](https://tools.ietf.org/html/rfc3339) `date-time`
        UTC format: `YYYY-MM-DDThh:mm:ss.sssZ`.
      type: string
      minLength: 20
      maxLength: 30
      format: date-time
      x-apiture-since: 1.18.0
      example: '2021-10-30T19:06:04.250Z'

    readOnlyTimestamp:
      title: Read-Only Timestamp
      description: >-
        A readonly or derived timestamp (an instant in time) formatted in [RFC 3339](https://tools.ietf.org/html/rfc3339) `date-time`
        UTC format: `YYYY-MM-DDThh:mm:ss.sssZ`.
      allOf:
        - $ref: '#/components/schemas/timestamp'
      readOnly: true