diff --git a/lib/classes/session/manager.php b/lib/classes/session/manager.php
index 61f3c2b7ff6..4ce12f52ac8 100644
--- a/lib/classes/session/manager.php
+++ b/lib/classes/session/manager.php
@@ -89,7 +89,9 @@ class manager {
     public static function restart_with_write_lock(bool $readonlysession) {
         global $CFG;
 
-        self::$requireslockdebug = !$readonlysession;
+        if (!empty($CFG->enable_read_only_sessions_debug)) {
+            self::$requireslockdebug = !$readonlysession;
+        }
 
         if (self::$sessionactive && !self::$handler->requires_write_lock()) {
             @self::$handler->abort();