As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED. DURING CABIN INTERCOMMUNICATION DATA SYSTEM 1 EMERGENCY POWER SUPPLY UNIT SYSTEM TEST, DISCOVERED "BATTERY/EMERGENCY POWER SUPPLY UNIT (10WL) FORWARD LEFT" MESSAGE. REMOVED AND REPLACED BATTERY OF EMERGENCY POWER SUPPLY UNIT (10WL), PER AMM 33-51-38.