Index: sites/all/modules/contrib/metatag/metatag.module
===================================================================
--- sites/all/modules/contrib/metatag/metatag.module	(revision 19791)
+++ sites/all/modules/contrib/metatag/metatag.module	(working copy)
@@ -2010,7 +2010,7 @@
             // We need to pop entity from contexts array.
             $first_context = array_pop($context['contexts']);
             // Only if the context actually exists, which would be an entity.
-            if (!empty($first_context->data)) {
+            if (!empty($first_context->data) && is_object($first_context->data)) {
               $langcode = $GLOBALS['language_content']->language;
               metatag_entity_view($first_context->data, $entity_type, 'full', $langcode, TRUE);
             }