diff --git a/CRM/Contact/Form/Task/PDFLetterCommon.php b/CRM/Contact/Form/Task/PDFLetterCommon.php
index c5b8439801d0..a0424e1d6cf7 100644
--- a/CRM/Contact/Form/Task/PDFLetterCommon.php
+++ b/CRM/Contact/Form/Task/PDFLetterCommon.php
@@ -180,7 +180,7 @@ public static function postProcess(&$form) {
     }
 
     $tee = NULL;
-    if ($isLiveMode && Civi::settings()->get('recordGeneratedLetters') === 'combined-attached') {
+    if (self::isLiveMode($form) && Civi::settings()->get('recordGeneratedLetters') === 'combined-attached') {
       if (count($activityIds) !== 1) {
         throw new CRM_Core_Exception("When recordGeneratedLetters=combined-attached, there should only be one activity.");
       }