gistfile1.php

<?php
/**
* disables a fast 404 optimization
**/

function wpewa20140105() {
  header('wpengine-workaround-20140105: present');
  $unhook = array(WpeCommon::instance(), 'is_404');
  remove_action('template_redirect', $unhook, 100);
  remove_action('bp_init', $unhook, 100);
}

add_action('init', 'wpewa20140105', 100);

Score.