Issue #3336160: When preview a new node with a paragraph : Cannot load the "paragraph" entity with NULL ID

src/Calculate/ReadingTime.php

@@ -162,6 +162,11 @@ class ReadingTime {
               ->getValue();
 
             foreach ($list as $item) {
+              // If we are in preview mode, paragraphs are still unknown.
+              if (is_null($item['target_id'])) {
+                continue;
+              }
+
               $referenceRevisionEntity = $this->entityTypeManager
                 ->getStorage($entityType)
                 ->load($item['target_id']);