Ticket #31570: 31570.diff

wp-admin/includes/ajax-actions.php

@@ -2376 +2376 @@
         $query = new WP_Query( $query );
 
         $posts = array_map( 'wp_prepare_attachment_for_js', $query->posts );
-        $posts = array_filter( $posts );
+        $posts = array_values( array_filter( $posts ) );
 
         wp_send_json_success( $posts );
 }