As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A RAMP INSPECTION BY THE LOCAL CAA (MXP), IT WAS NOTED (ON LOG PAGE 236495) THAT THE EMERGENCY EXIT LIGHTING (RIGHT OVERWING) WAS NOT OPERATIONAL. TROUBLESHOOTING INDICATED A BATTERY PACK WAS NOT FUNCTIONAL. THIS WAS CONFIRMED BY A SWAP OF THE BATTERY PACK WITH ANOTHER FOR THE FORWARD SECTION BULLNOSE EMERGENCY LIGHTS (A DEFERRABLE ITEM). THE AIRCRAFT THEN DEPARTED WITHOUT INCIDENT AND THE FAULTY BATTERY WAS SINCE REPLACED, CLEARING THE DMI.