As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: SHORTLY AFTER REACHING CRUISE ALTITUDE ALL CABIN EMERGENCY LIGHTS CAME ON. ALL ATTEMPTS TO TURN THEM OFF WERE UNSUCCESSFUL. LIGHTS CYCLED OFF/ON FOR REMAINDER OF FLIGHT. EICAS MESSAGE: EMERGENCY LIGHTS. REPLACED P081 ATTENDANT SWITCH PANEL (AALA202109136073) AND WINDOW HEAT/EMERGENCY LIGHTS MODULE (AALA202109132075) IAW 33-22-06-01A-720AA AND AMM 30-41-02-009-720A-A.