The ClientConfiguration (not to be confused with the JAXRS Configuration) is lost when a user of the JAXRS Client APIs calls path(...) on a WebTarget with a template. The ClientConfiguration contains important pieces like Interceptors, etc. that would be lost when the user tries to invoke the method on the WebTarget returned from the path(...) method.
For example, we create an out interceptor and add it to the ClientConfiguration, and we would expect that interceptor to be executed on every outbound request, but the following example shows that it is not:
Client client = ClientBuilder.newClient();
WebTarget target = client.target("http://localhost:8080/myRoot");
target.request().get(); // works - invokes the interceptor
WebTarget target2 = target.path("/path/
target2.request().get(); // fails - request is sent without invoking the interceptor