diff --git a/core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php b/core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
index f5ebb8c..e98efac 100644
--- a/core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
+++ b/core/modules/datetime_range/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
@@ -61,6 +61,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
         }
 
         if (!empty($item->_attributes)) {
+          $elements[$delta] += array('#attributes' => array());
           $elements[$delta]['#attributes'] += $item->_attributes;
           // Unset field item attributes since they have been included in the
           // formatter output and should not be rendered in the field template.