Twitter Open API Spec not validating

I'm trying to add the twitter open API spec (https://api.twitter.com/labs/2/openapi.json) to Azure API Management and it is not validating. The spec appears to be valid and Swagger renders it without issue.

I'm getting the following issues below.. Any help would be much appreciated.

One or more fields contain incorrect values:

Parsing error(s): Schema Problem must contain property specified in the discriminator type in the required field list. [#/components/schemas/Problem/discriminator]

Parsing error(s): The input OpenAPI file is not valid for the OpenAPI specification https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md (schema https://github.com/OAI/OpenAPI-Specification/blob/master/schemas/v3.0/schema.yaml).