Invalid references do not throw parser error

In the attached open API document, the response schema is referencing a parameter rather than a schema. This is an invalid use case and should throw an error during parsing. I noticed when $refs are invalid, they usually are not validated correctly.

How should the implementation handle this scenario? Should it throw an error? Should it ignore that response or schema?

There needs to be a consistent approach in handling this, and hence I'm asking this question.

openapi: 3.0.1
info:
title: Swagger Petstore
description: 'This is a sample server Petstore server'
version: 1.0.0
servers:

• url: http://mytestServer/{v1}
  variables:
  v2:
  default: 'd'
  paths:
  '/pet/{petId}':
  get:
  parameters:
  - $ref: '#/components/parameters/P1'
  responses:
  '200':
  $ref: '#/components/responses/R1'
  components:
  responses:
  R1:
  description: The specified resource was not found
  content:
  application/json:
  schema:
  $ref: '#/components/parameters/P1'
  parameters:
  P1:
  in: path
  name: petId
  schema:
  type: string
  required: true

Start by reproducing the embedded OpenAPI 3.0.1 document in the parser and trace how the response schema resolves its $ref to components/parameters/P1. Determine the consistent behavior for this invalid reference, then verify that parsing handles it accordingly for the response schema and related invalid references.