Unexpected term id

This happens with anonymous users, I have debugged and cannot reproduce:

  $node=node_load(9806);
  $tids = array();

  // Get the vids that tac_lite cares about.
  $vids = variable_get('tac_lite_categories', NULL);
  if ($vids) {
    // Load all terms found in term reference fields.
    // This logic should work for all nodes (published or not).
    $terms_by_vid = tac_lite_node_get_terms($node);
    if (!empty($terms_by_vid)) {
      foreach ($vids as $vid) {
        if (!empty($terms_by_vid[$vid])) {
          foreach ($terms_by_vid[$vid] as $tid => $term) {
            $tids[$tid] = $tid;
          }
        }
      }
    }

   $query = db_select('taxonomy_index', 'r');
    $t_alias = $query->join('taxonomy_term_data', 't', 'r.tid = t.tid');
    $v_alias = $query->join('taxonomy_vocabulary', 'v', 't.vid = v.vid');
    $query->fields( $t_alias );
    $query->condition("r.nid", $node->nid);
    $query->condition("t.vid", $vids, 'IN');
    $result = $query->execute();
    foreach ($result as $term) {
      if (empty($tids[$term->tid])) {
        print 'empty';
      }
      else{
        print 'found '.$tids[$term->tid];
      }
    }
}

scaringly when this happens, no access denied occurrs so the access control fails....

I have added some debug statements and the tid's array is an empty array when this happens, which is not every time, very strange

    foreach ($result as $term) {
      if (empty($tids[$term->tid])) {
        watchdog('tac_lite', 'Unexpected term id %tid associated with !node.  Please report this to !url.', array(
            '%tid' => $term->tid,
            '!node' => l($node->title, 'node/' . $node->nid),
            '!url' => 'https://drupal.org/node/1918272',
          ), WATCHDOG_DEBUG);
          /////////////////////////////////// DEBUG /////////////////////////////////////////////////////
          watchdog('tac_lite_debug - Unexpected term id', $term->tid . ' not found tids=<pre>'.htmlspecialchars(print_r($tids,1)).'</pre>');
          watchdog('tac_lite_debug - Unexpected term id', 'vids=<pre>'.htmlspecialchars(print_r($vids,1)).'</pre>');
          watchdog('tac_lite_debug - Unexpected term id', 'terms_by_vid=<pre>'.htmlspecialchars(print_r($terms_by_vid,1)).'</pre>');
          /////////////////////////////////// DEBUG /////////////////////////////////////////////////////
      }

results

vids=Array
(
    [8] => 8
)

terms_by_vid=Array
(
    [9] => Array
        (
            [470] => stdClass Object
                (
                    [tid] => 470
                    [vid] => 9
                    [name] => SESS
                    [description] => In event type SESS
                    [format] => 
                    [weight] => 20
                    [vocabulary_machine_name] => vocabulary_9
                )

        )

)

 tids=Array
(
)

I am using a term reference from /admin/structure/types/manage/campus_event/fields

flakey database API?

The plot thickens, I think this happens when cron is sending content to apachesolr

correct data, from another debug statement:

terms_by_vid=
Array
(
    [9] => Array
        (
            [470] => stdClass Object
                (
                    [tid] => 470
                    [vid] => 9
                    [name] => SESS
                    [description] => In event type SESS
                    [format] => 
                    [weight] => 20
                    [vocabulary_machine_name] => vocabulary_9
                )

        )

    [8] => Array
        (
            [32] => stdClass Object
                (
                    [tid] => 32
                    [vid] => 8
                    [name] => All
                    [description] => Can be seen by everyone (EBI, WTSI, Wellcome Trust).
Note: You must use this option if you wish events to appear in email bulletins.
                    [format] => 
                    [weight] => 0
                    [vocabulary_machine_name] => vocabulary_8
                )

        )

)
vids=
Array
(
    [8] => 8
)
 tids=
Array
(
    [32] => 32
)

does not happen if you index data as a logged in admin user

tac_lite_node_get_terms is missing a return value when cron runs

I think this has to do with node_load not having the term id for anonymous, as this is used in tac_lite_node_get_terms, I have a scheme for Visibility and Visibility on create and edit forms, I have allowed this term for anon, so it shows up when you view nodes as anon, so therefore is available upon node_load for anon, so this should have fixed the issue, didn't throw errors with previous versions, but looks like it was a configuration issue, so this may have fixed the issue, will find out on tomorrows cron?
Thanks for the time,
Stephen :)