Workaround, add this to the functions.php in the current theme folder:
// Remove bug in WordPress SEO by Yoast where Author achive is not working
global $wpseo_front;
remove_action( 'wp', array( $wpseo_front, 'archive_redirect' ), '10' );
I have experienced that sometimes I help to press update two times in the Permalink Settings. That way you are sure that the .htaccess is set correct up and that all url is flushed