Hi, I think this should be a easy fix. Some time the file logs.php changed to admin_logs.php (I supose), so the link on notifications dropdown is broken. I searched for the logs.php link and found it on cron.php line 972
mysqli_query($mysqli, "INSERT INTO notifications SET notification_type = 'Cron', notification = 'Cron successfully executed', notification_action = 'logs.php'");
Hope this help!