diff --git a/src/Entity/Paragraph.php b/src/Entity/Paragraph.php
index ed65403..bcbaaf0 100644
--- a/src/Entity/Paragraph.php
+++ b/src/Entity/Paragraph.php
@@ -563,6 +563,15 @@ class Paragraph extends ContentEntityBase implements ParagraphInterface, EntityN
           $summary_count += $paragraph_entity->getSummaryCount();
         }
       }
+      // If we start with the closed summary the $value['entity'] is not
+      // calculated so we load the entity ourselves.
+      elseif (isset($value['target_id']) && isset($value['target_revision_id'])) {
+        $paragraph_entity = \Drupal::entityTypeManager()
+          ->getStorage('paragraph')
+          ->loadRevision($value['target_revision_id']);
+        $summary[] = $paragraph_entity->getSummary();
+        $summary_count += $paragraph_entity->getSummaryCount();
+      }
     }
 
     return \Drupal::translation()
diff --git a/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php b/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php
index d4b4c61..f40f4fa 100644
--- a/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php
+++ b/src/Tests/Experimental/ParagraphsExperimentalBehaviorsTest.php
@@ -190,7 +190,7 @@ class ParagraphsExperimentalBehaviorsTest extends ParagraphsExperimentalTestBase
     // Assert that the summary includes the text of the behavior plugins.
     $this->clickLink('Edit');
     $this->assertRaw('class="paragraphs-collapsed-description">first_paragraph, Text color: blue, Bold: Yes');
-    $this->assertRaw('class="paragraphs-collapsed-description">0 Children | , Bold: Yes');
+    $this->assertRaw('class="paragraphs-collapsed-description">1 Child | nested_paragraph, Text color: blue, Bold: No, Bold: Yes');
   }
 
   /**