When connecting to a server that uses Negoiate for the WWW-authenticate header then it will not respond correctly

When connecting to a server that uses Negoiate for the WWW-authenticate header then it will not respond correctly. The server sends the following as the headers for a request:

HTTP/1.1 401 Unauthorized
Content-Type: text/plain;charset=utf-8
Content-Length: 0
WWW-Authenticate: Basic realm="rdwebservices"
WWW-Authenticate: NTLM
WWW-Authenticate: Negotiate

and it will respond with:

'Authorization: Negotiate '

which does not contain the code needed to authorize. This is working fine on Windows so appears to be macOS specific and can be reproduced with the http example connecting to a standard IIS server.