Custom Permalinks and filters?

Maybe in the custom_rewrite function, try concatenating $wp_rewrite->rules and $feed_rules using array_merge, then returning $wp_rewrite.

function custom_rewrite( $wp_rewrite ) {
  $feed_rules = array(
    'local/(.*?)/(.*?)/?$'  =>  'index.php?page_id=41&trade=" . $wp_rewrite->preg_index(1)."&area=" . $wp_rewrite->preg_index(2),
    "local/(.*?)/(.*?)?$'  =>  'index.php?page_id=41&trade=" . $wp_rewrite->preg_index(1)."&area=" . $wp_rewrite->preg_index(2),
  );
  $wp_rewrite->rules = array_merge($feed_rules, $wp_rewrite->rules);
  return $wp_rewrite;
}

I haven”t tested that at all, just a suggestion of something to be looking at.