diff --git a/code/Extension/UserFormFieldEditorExtension.php b/code/Extension/UserFormFieldEditorExtension.php
index 4ea34e6..8da76a7 100644
--- a/code/Extension/UserFormFieldEditorExtension.php
+++ b/code/Extension/UserFormFieldEditorExtension.php
@@ -42,6 +42,8 @@ class UserFormFieldEditorExtension extends DataExtension
     );
 
     private static $owns = [
+        // Note we explicitly cannot use $cascade_duplicates to duplicate this relation.
+        // See onAfterDuplicate()
         'Fields'
     ];
 
@@ -234,13 +236,14 @@ class UserFormFieldEditorExtension extends DataExtension
     }
 
     /**
-     * When duplicating a UserDefinedForm, duplicate all of its fields and display rules
+     * Duplicate the Fields() relation.
+     * When duplicating a UserDefinedForm, ensure the group ends aren't duplicated twice,
+     * but also ensure they are connected to the correct duplicated Group.
      *
      * @see DataObject::duplicate
      * @param DataObject $oldPage
      * @param bool $doWrite
-     * @param string $manyMany
-     * @return DataObject
+     * @param null|array $manyMany
      */
     protected function onAfterDuplicate($oldPage, $doWrite, $manyMany)
     {
@@ -249,10 +252,7 @@ class UserFormFieldEditorExtension extends DataExtension
         foreach ($oldPage->Fields() as $field) {
             /** @var EditableFormField $newField */
             $newField = $field->duplicate(false);
-            $newField->ParentID = $this->owner->ID;
-            $newField->ParentClass = $this->owner->ClassName;
-            $newField->Version = 0;
-            $newField->write();
+            $this->getOwner()->Fields()->add($newField);
 
             // If we encounter a group start, record it for later use
             if ($field instanceof EditableFieldGroup) {
@@ -265,13 +265,6 @@ class UserFormFieldEditorExtension extends DataExtension
                 $groupStart->EndID = $newField->ID;
                 $groupStart->write();
             }
-
-            foreach ($field->DisplayRules() as $customRule) {
-                $newRule = $customRule->duplicate(false);
-                $newRule->ParentID = $newField->ID;
-                $newRule->Version = 0;
-                $newRule->write();
-            }
         }
     }
 
diff --git a/code/Model/EditableFormField.php b/code/Model/EditableFormField.php
index 2299e90..660bfb9 100755
--- a/code/Model/EditableFormField.php
+++ b/code/Model/EditableFormField.php
@@ -181,7 +181,9 @@ class EditableFormField extends DataObject
         'DisplayRules',
     ];
 
-    private static $cascade_duplicates = false;
+    private static $cascade_duplicates = [
+        'DisplayRules',
+    ];
 
     /**
      * This is protected rather that private so that it's unit testable
diff --git a/code/Model/EditableFormField/EditableMultipleOptionField.php b/code/Model/EditableFormField/EditableMultipleOptionField.php
index feb2a98..a8f76fb 100644
--- a/code/Model/EditableFormField/EditableMultipleOptionField.php
+++ b/code/Model/EditableFormField/EditableMultipleOptionField.php
@@ -55,6 +55,10 @@ class EditableMultipleOptionField extends EditableFormField
         'Options',
     ];
 
+    private static $cascade_duplicates = [
+        'Options',
+    ];
+
     private static $table_name = 'EditableMultipleOptionField';
 
     /**
@@ -112,25 +116,6 @@ class EditableMultipleOptionField extends EditableFormField
         return $fields;
     }
 
-    /**
-     * Duplicate a pages content. We need to make sure all the fields attached
-     * to that page go with it
-     * {@inheritDoc}
-     */
-    public function duplicate(bool $doWrite = true, array|null $relations = null): static
-    {
-        $clonedNode = parent::duplicate(true);
-
-        foreach ($this->Options() as $field) {
-            $newField = $field->duplicate(false);
-            $newField->ParentID = $clonedNode->ID;
-            $newField->Version = 0;
-            $newField->write();
-        }
-
-        return $clonedNode;
-    }
-
     /**
      * Return whether or not this field has addable options such as a
      * {@link EditableDropdown} or {@link EditableRadioField}
diff --git a/code/Model/Recipient/EmailRecipient.php b/code/Model/Recipient/EmailRecipient.php
index d0ceef3..91ce210 100644
--- a/code/Model/Recipient/EmailRecipient.php
+++ b/code/Model/Recipient/EmailRecipient.php
@@ -107,6 +107,10 @@ class EmailRecipient extends DataObject
         'CustomRules',
     ];
 
+    private static $cascade_duplicates = [
+        'CustomRules',
+    ];
+
     private static $summary_fields = [
         'EmailAddress',
         'EmailSubject',
diff --git a/code/UserForm.php b/code/UserForm.php
index fae5120..66b44fc 100644
--- a/code/UserForm.php
+++ b/code/UserForm.php
@@ -121,7 +121,9 @@ trait UserForm
         'EmailRecipients',
     ];
 
-    private static $cascade_duplicates = false;
+    private static $cascade_duplicates = [
+        'EmailRecipients',
+    ];
 
     /**
      * @var array
@@ -168,9 +170,8 @@ trait UserForm
     private static $non_live_permissions = ['SITETREE_VIEW_ALL'];
 
     /**
-     * Temporary storage of field ids when the form is duplicated.
-     * Example layout: array('EditableCheckbox3' => 'EditableCheckbox14')
-     * @var array
+     * Unused property
+     * @deprecated 5.3.0 Will be removed without equivalent functionality to replace it
      */
     protected $fieldsFromTo = [];
 
diff --git a/tests/php/Model/UserDefinedFormTest.php b/tests/php/Model/UserDefinedFormTest.php
index c434201..e538d19 100644
--- a/tests/php/Model/UserDefinedFormTest.php
+++ b/tests/php/Model/UserDefinedFormTest.php
@@ -363,7 +363,7 @@ class UserDefinedFormTest extends FunctionalTest
         $form2 = $this->objFromFixture(UserDefinedForm::class, 'page-with-group');
         $form2Validator = new UserFormValidator();
         $form2Validator->setForm(new Form(new Controller(), Form::class, new FieldList(), new FieldList()));
-        $this->assertTrue($form2Validator->php($form2->toMap()));
+        $this->assertTrue($form2Validator->php($form2->toMap()), json_encode($form2Validator->getResult()->getMessages()));
 
         // Check field groups exist
         $form2GroupStart = $form2->Fields()->filter('ClassName', EditableFieldGroup::class)->first();
@@ -374,7 +374,7 @@ class UserDefinedFormTest extends FunctionalTest
         $form3 = $form2->duplicate();
         $form3Validator = new UserFormValidator();
         $form3Validator->setForm(new Form(new Controller(), Form::class, new FieldList(), new FieldList()));
-        $this->assertTrue($form3Validator->php($form3->toMap()));
+        $this->assertTrue($form3Validator->php($form3->toMap()), json_encode($form3Validator->getResult()->getMessages()));
         // Check field groups exist
         $form3GroupStart = $form3->Fields()->filter('ClassName', EditableFieldGroup::class)->first();
         $form3GroupEnd = $form3->Fields()->filter('ClassName', EditableFieldGroupEnd::class)->first();