FIX Ensure duplicated multiple option field is written (has an ID) before duplicating options

code/Extension/UserFormFieldEditorExtension.php

@@ -225,6 +225,7 @@ class UserFormFieldEditorExtension extends DataExtension
         // List of EditableFieldGroups, where the key of the array is the ID of the old end group
         $fieldGroups = [];
         foreach ($oldPage->Fields() as $field) {
+            /** @var EditableFormField $newField */
             $newField = $field->duplicate(false);
             $newField->ParentID = $this->owner->ID;
             $newField->ParentClass = $this->owner->ClassName;

code/Model/EditableFormField/EditableMultipleOptionField.php

@@ -123,7 +123,7 @@ class EditableMultipleOptionField extends EditableFormField
             $manyMany = null;
         }
 
-        $clonedNode = parent::duplicate($doWrite, $manyMany);
+        $clonedNode = parent::duplicate(true, $manyMany);
 
         foreach ($this->Options() as $field) {
             /** @var EditableOption $newField */