[BUG][JAVA] $ref not working correctly

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

We have the following swagger folder structure in our project:

- api
    - endpoints
    - schemas
    - common-elements (git submodule)
       - default-endpoints
          - Healthcheck.yml
       - default-schemas
          DefaultHeaders.yml
          Error.yml
- main_api.yml  
  

Now in the Healthcheck file we have the following code which is referencing stuff in the common-elements git submodule:

500:
  description: Error on TCS side
  headers:
    cobaActivityID:
      $ref: "../common-elements/headers/DefaultHeaders.yaml#/Response/cobaActivityID"
    cobaMachineName:
      $ref: "../common-elements/headers/DefaultHeaders.yaml#/Response/cobaMachineName"
  content:
    application/json;charset=utf-8:
      schema:
        $ref: "../common-elements/schemas/Error.yaml#/Error"

With this setup we get the following error on generation and even on the teamcity build it is not working.

[WARNING] Exception while resolving:
java.lang.RuntimeException: Unable to load RELATIVE ref: ./common-elements/default-endpoints/common-elements/default-schemas/Error.yaml path: C:\dev\bitbucket\test\api

When we change $ref: "../common-elements/schemas/Error.yaml#/Error" for $ref: "./schemas/Error.yaml#/Error" it is working. But we only need to change it for the schema.

I need your help now. What is wrong here and what would be the correct referencing of the files?

openapi-generator version

5.3.0

Generation Details

mvn clean generate-sources

Steps to reproduce

See above

Start with the shown Healthcheck YAML, the referenced DefaultHeaders.yaml and Error.yaml files, and the main_api.yml entry point. Reproduce the path-resolution warning with mvn clean generate-sources using openapi-generator 5.3.0, then compare how the header and schema references are resolved. Done means the documented relative references resolve correctly during generation.