I'm not sure why my Drupal site is calling the _bio_should_add_nid() function without an object in the view parameter, but in any case I've been getting a ton of errors like these in my watchdog table:

Invalid argument supplied for foreach() in [path]\modules\bio\bio_views.inc on line 259.

My solution is to change lines 259 and 265 so that they have an if (is_array($view->field)) before the foreach ($view->field as $field) (and the same for $filter).

I guess in an ideal world, the foreach() operator would be smart enough to just ignore arguments that are not arrays, but since it's not, we can at least prevent errors this way.