As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN POWER IS DISCONNECTED AND EMERGENCY LIGHTS ARE SUPPOSED TO TRIGGER ON, ONLY THE REAR CABIN EXIT SIGN AND OVERHEAD LIGHTS AT SEAT ROWS 19 AND 28 ILLUMINATE. FOUND (10WL , 11WL AND 12WL) EPSU BATTERY TO BE FAULTING REPLACED ALL 3 BATTERY IAW AMM 33-51-38 PB 401.