Bug in EntityFieldQueryExtra_entity_create_kill_null()

I found that EntityFieldQueryExtra_entity_create_kill_null() was attempting to process property members of entities as if they were fields. I haven't dug into the workings of EFQE so don't know why this is happening, but adding a check to see if the member to be processed is an array at least got it working (it was bringing down the whole site, hence critical status):

function EntityFieldQueryExtra_entity_create_kill_null(&$object) {
  foreach ($object as $key => $values) {
    if (!isset($values['und']) || !is_array($values['und'])) { // Add is array check to filter out property members.
      continue;
    }
    $all_null = TRUE;
    foreach ($values['und'] as $delta => $data) {
      foreach ($data as $info) {
        if (!is_null($info)) {
          $all_null = FALSE;
          break 2;
        }
      }
    }
    if ($all_null) {
      unset($object->{$key}['und']);
      $object->{$key} = array();
    }
  }
}