As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AT CRUISE, FLIGHT ATTENDANT REPORTED AFT OVERHEAD EXIT LIGHT ILLUMINATED ALONG WITH DOOR 2LEFT/RIGHT EXIT LIGHTS. TROUBLESHOOT EPSU PER TSM 33-51-00-810-801-A. FAULT EMERGENCY POWER SUPPLY UNIT BATTERY FOUND. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT IAW AMM 323-51-38.