This is our fault and I apologise profusely. The API docs are actually wrong - there’s a small issue with the autogeneration of the openAPI3 spec which we are working actively on - but this means that the current API spec doesn’t reflect the API server’s current setup.
Really sorry about this - this is a misconfiguration of our API management layer related to some changes to the openAPI3 spec. It’s not you, it’s us. We are on the case and aim to fix it in the next week. Is that going to cause unacceptable delay for you? I might be able to sort out another option for the interim if so.