diff --git a/includes/signup_edit_form.inc b/includes/signup_edit_form.inc
index 0fe545e..69bb232 100644
--- a/includes/signup_edit_form.inc
+++ b/includes/signup_edit_form.inc
@@ -142,7 +142,7 @@ function signup_validate_anon_mail($form, &$form_state) {
  * Submit callback when saving changes to an existing signup.
  */
 function signup_edit_form_save_submit($form, $form_state) {
-  $signup = $form['#signup'];
+  $signup = drupal_clone($form['#signup']);
   if (!empty($form_state['values']['signup_form_data'])) {
     $signup->form_data = $form_state['values']['signup_form_data'];
   }