As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 4155, DURING MAINTENANCE INSPECTION THE LEFT HAND OVER WING EXIT SHROUD EXIT MARKER FAILED TO ILLUMINATE. MAINTENANCE REMOVED AND REPLACED THE #4 INVERTER, OPERATIONALLY TESTED WITH NO DEFECTS AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.