As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: APU AGENT DISCHARGE LIGHT ON OVERHEAD PANEL ILLUMINATED IN CRUISE AND WENT OUT ON LANDING. MAINTENANCE VERIFIED THAT THE BOTTLE HAD NOT DISCHARGED AND INDICATED GOOD. A SATISFACTORY OPERATIONAL CHECK OF THE APU FIRE TEST SYSTEM WAS ACCOMPLISHED WITH NO DEFECT NOTED PER AMM 26-13-00.