As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN EMERG LIGHT: WHILE IN CRUISE NOTICED ALL EMERGENCY LIGHTS IN THE CABIN ON WHILE THE EMER LT SWITCH WAS IN THE ARM POSITION. "CORRECTIVE ACTION" REMOVED FAULTY AFT EMERGENCY BATTERY AND INSTALLED NEW BATTERY IAW EMB505 AMM 33-52-01 OPS CHECKS GOOD. PN/SN ON 7450LS00 / 006551 PN/SN OFF 7450LS-00 / 005207