diff --git a/lib/external/externallib.php b/lib/external/externallib.php
index 4de979b1acc44..ba8aa4046a3b3 100644
--- a/lib/external/externallib.php
+++ b/lib/external/externallib.php
@@ -321,6 +321,8 @@ public static function get_fragment($component, $callback, $contextid, $args = n
         self::validate_context($context);
         $arguments['context'] = $context;
 
+        // Hack alert: Set a default URL to stop the annoying debug.
+        $PAGE->set_url('/');
         // Hack alert: Forcing bootstrap_renderer to initiate moodle page.
         $OUTPUT->header();