diff --git a/lib/external/classes/util.php b/lib/external/classes/util.php
index d62ce8444d8a9..8c63a763ebd73 100644
--- a/lib/external/classes/util.php
+++ b/lib/external/classes/util.php
@@ -543,8 +543,8 @@ public static function format_text(
             return ['', $textformat ?? FORMAT_MOODLE];
         }
 
-        if (empty($itemid)) {
-            $itemid = null;
+        if ($itemid !== null) {
+            $itemid = (int) $itemid;
         }
 
         // Get settings (singleton).