Ticket #25938: 25938.1.diff

wp-content/themes/twentyfourteen/functions.php

@@ -415 +415 @@
  * Extend the default WordPress post classes.
  *
  * Adds a post class to denote:
- * Non-password protected page with a post thumbnail.
+ * Non-password protected page or post, with a post thumbnail, and not outside
+ * the loop.
  *
  * @since Twenty Fourteen 1.0
  *
@@ -423 +424 @@
  * @return array The filtered post class list.
  */
 function twentyfourteen_post_classes( $classes ) {
-        if ( ! post_password_required() && has_post_thumbnail() )
+        if ( in_the_loop() && ! post_password_required() && has_post_thumbnail() )
                 $classes[] = 'has-post-thumbnail';
         else
                 $classes[] = 'no-post-thumbnail';