OpenAPI Spec is Invalid

Hi, I’m trying to generate a client for the Rasa Open source Http API (http-api) using the openAPI generator (openapi). I am however getting an error from the generator stating that the spec is invalid:

Exception in thread "main" org.openapitools.codegen.SpecValidationException: There were issues with the specification. The option can be disabled via validateSpec (Maven/Gradle) or --skip-validate-spec (CLI).
 | Error count: 1, Warning count: 1
Errors:
        -attribute components.schemas.YAMLTrainingRequest.items is missing

Is there a specific version of the generator that has to be used? I didn’t find anything about this in the docs.

This is still the case. I just tried with latest stable Rasa, Can anyone suggest how to proceed with this?