diff --git a/src/Plugin/Field/FieldWidget/ParagraphsWidget.php b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
index b4beec0..1104a79 100644
--- a/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
+++ b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
@@ -1200,7 +1200,7 @@ class ParagraphsWidget extends WidgetBase {
 
     $user_input = $form_state->getUserInput();
     $duplicate_input = $user_input[$field_name][$delta];
-    array_splice($user_input[$field_name], $delta, 0, [$duplicate_input]);
+    array_splice($user_input[$field_name], $delta + 1, 0, [$duplicate_input]);
     $form_state->setUserInput($user_input);
 
     // Create the duplicated paragraph and insert it below the original.
@@ -1210,7 +1210,7 @@ class ParagraphsWidget extends WidgetBase {
       'mode' => 'edit'
     ];
 
-    array_splice($widget_state['paragraphs'], $delta, 0, $paragraph);
+    array_splice($widget_state['paragraphs'], $delta +1 , 0, $paragraph);
 
     static::setWidgetState($parents, $field_name, $form_state, $widget_state);
     $form_state->setRebuild();
diff --git a/src/Tests/Experimental/ParagraphsExperimentalDuplicateFeatureTest.php b/src/Tests/Experimental/ParagraphsExperimentalDuplicateFeatureTest.php
index a27922d..b3f59d0 100644
--- a/src/Tests/Experimental/ParagraphsExperimentalDuplicateFeatureTest.php
+++ b/src/Tests/Experimental/ParagraphsExperimentalDuplicateFeatureTest.php
@@ -34,10 +34,11 @@ class ParagraphsExperimentalDuplicateFeatureTest extends ParagraphsExperimentalT
     $this->drupalPostAjaxForm('node/add/paragraphed_test', [], 'field_paragraphs_text_paragraph_add_more');
 
     // Create a node with a Paragraph.
-    $text = 'recognizable_text';
+    $text_01 = 'recognizable_text_01';
+    $text_02 = 'recognizable_text_02';
     $edit = [
       'title[0][value]' => 'paragraphs_mode_test',
-      'field_paragraphs[0][subform][field_text][0][value]' => $text,
+      'field_paragraphs[0][subform][field_text][0][value]' => $text_01,
     ];
     $this->drupalPostFormSave(NULL, $edit, t('Save and publish'), t('Save'), $edit + ['status[value]' => TRUE]);
     $node = $this->drupalGetNodeByTitle('paragraphs_mode_test');
@@ -49,12 +50,36 @@ class ParagraphsExperimentalDuplicateFeatureTest extends ParagraphsExperimentalT
     // Click "Duplicate" button.
     $this->drupalPostAjaxForm(NULL, [], 'field_paragraphs_0_duplicate');
     $this->drupalPostAjaxForm(NULL, [], 'field_paragraphs_0_edit');
-    $this->assertFieldByName('field_paragraphs[0][subform][field_text][0][value]', $text);
-    $this->assertFieldByName('field_paragraphs[1][subform][field_text][0][value]', $text);
+    $this->assertFieldByName('field_paragraphs[0][subform][field_text][0][value]', $text_01);
+    $this->assertFieldByName('field_paragraphs[1][subform][field_text][0][value]', $text_01);
 
     // Save and check if both paragraphs are present.
-    $this->drupalPostFormSave(NULL, $edit, t('Save and keep published'), t('Save'));
-    $this->assertNoUniqueText($text);
+    $this->drupalPostFormSave(NULL, [], t('Save and keep published'), t('Save'));
+    $this->assertNoUniqueText($text_01);
+
+    // Try that again in open mode.
+    $this->setParagraphsWidgetMode('paragraphed_test', 'field_paragraphs', 'open');
+    $node = $this->drupalGetNodeByTitle('paragraphs_mode_test');
+    $this->drupalGet('node/' . $node->id() . '/edit');
+    $edit = [
+      'field_paragraphs[0][subform][field_text][0][value]' => $text_01,
+      'field_paragraphs[1][subform][field_text][0][value]' => $text_02,
+    ];
+    $this->drupalPostFormSave(NULL, $edit, t('Save and publish'), t('Save'), $edit + ['status[value]' => TRUE]);
+
+    $node = $this->drupalGetNodeByTitle('paragraphs_mode_test');
+    $this->drupalGet('node/' . $node->id() . '/edit');
+
+    $this->drupalPostAjaxForm(NULL, [], 'field_paragraphs_0_duplicate');
+    $this->assertFieldByName('field_paragraphs[0][subform][field_text][0][value]', $text_01);
+    $this->assertFieldByName('field_paragraphs[1][subform][field_text][0][value]', $text_01);
+    $this->assertFieldByName('field_paragraphs[2][subform][field_text][0][value]', $text_02);
+
+    $this->drupalPostFormSave(NULL, [], t('Save and publish'), t('Save'));
+    $this->drupalGet('node/' . $node->id() . '/edit');
+    $this->assertFieldByName('field_paragraphs[0][subform][field_text][0][value]', $text_01);
+    $this->assertFieldByName('field_paragraphs[1][subform][field_text][0][value]', $text_01);
+    $this->assertFieldByName('field_paragraphs[2][subform][field_text][0][value]', $text_02);
   }
 
   /**