diff --git a/src/Plugin/FullcalendarViewProcessor/SmartDateProcessor.php b/src/Plugin/FullcalendarViewProcessor/SmartDateProcessor.php
index 20d8d4d..cae2512 100644
--- a/src/Plugin/FullcalendarViewProcessor/SmartDateProcessor.php
+++ b/src/Plugin/FullcalendarViewProcessor/SmartDateProcessor.php
@@ -79,8 +79,10 @@ class SmartDateProcessor extends FullcalendarViewProcessorBase {
       else {
         $values[0]['delta'] = 0;
         $values[0]['id'] = $row->_entity->id();
-        if (!empty($entries[$key])) {
-          $this->updateEntry($entries[$key], $values[0], $format);
+        $lookup_key = $values[0]['id'] . '-' . $values[0]['delta'];
+        $entries_index = $mappings[$lookup_key];
+        if (!empty($entries[$entries_index])) {
+          $this->updateEntry($entries[$entries_index], $values[0], $format);
         }
       }
     }