Using the correct User/Pass in basic authentication with Preemptive enabled in the new HTTP Module works fine. You send a single request with the Authorization field and you receive a 200.
But in the case when you use a wrong User/Pass, it send fine the Authorization field but when the server respond with a 401, the requester send a new requester trying to be authorize.
See the attached files with the comparison of how works the http-client (only 1 request) and how it works the requester (2 requests)
To reproduce you can use these tests:
HttpRequestAuthTestCase - invalidBasicAuthentication (Mule-ee) (Requeter - 2 requests)
HttpListenerAuthTestCase - invalidBasicAuthenticationPreemptive (Mule-ee) (Http-client 1 request)