diff --git a/libs/sysplugins/smarty_internal_extension_handler.php b/libs/sysplugins/smarty_internal_extension_handler.php
index f6f28e31..2600f22e 100644
--- a/libs/sysplugins/smarty_internal_extension_handler.php
+++ b/libs/sysplugins/smarty_internal_extension_handler.php
@@ -66,7 +66,7 @@ class Smarty_Internal_Extension_Handler
     public function _callExternalMethod(Smarty_Internal_Data $data, $name, $args)
     {
         /* @var Smarty $data ->smarty */
-        $smarty = $data->smarty ?? $data;
+        $smarty = isset($data->smarty) ? $data->smarty : $data; // don't use ?? for isset here since that would need a follow-up property define in Smarty class for __get()
         if (!isset($smarty->ext->$name)) {
             if (preg_match('/^((set|get)|(.*?))([A-Z].*)$/', $name, $match)) {
                 $basename = $this->upperCase($match[ 4 ]);