SPS errors when using Views with a relationship

Notice: Undefined property: stdClass::$nid in _sps_preprocess() (line 419 of /sites/all/modules/sps/sps.module).

As an example, looking at sps.module, line 419 we are iterating over $vars['view']->result

The code assumes that the result will contain an NID. However, these rows that are looped over may not always have $row->nid -- the data structure provided by fields that are brought in via references is quite different.

Not exactly sure what the best way to deal with this is, but in order to prevent errors I'm currently wrapping the loop in an isset() function.

416     case 'views_view_list':
417       if($vars['view']->base_table == 'node') {
418         foreach($vars['view']->result as $index => $row) {
419           if (isset($row->nid)) {
420             if ($class = $manager->react('add_class', array('id'=> $row->nid, 'type' => 'node'))) {
421               $vars['classes_array'][$index] .= " $class";
422             }
423           }
424         }
425       }
426     break;