As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FA/S REPORT EMER EXIT LIGHTS COMING ON/OFF DURING FLIGHT PERFORMED BITE CHECK OF THE EMERGENCY POWER SUPPLY UNITS REF AMM 33-51-00-710-001-A. FOUND FAULT EPSU UNIT FWD L PRESENT. PERFORMED TEST ON EPSU ABOVE DOOR AT 1L, UNIT FAULT LED ILLUMINATES. REMOVED AND REPLACED L FWD EPSU POWER SUPPLY 10WL AND BATTERY REF AMM 33-51-38-000-001-A/33-51-38-400-001-A. INSTALLATION TEST PASSED. LIGHTS NO LONGER TURN OFF/ON.