As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ACFT POWER-DOWN IT WAS DISCOVERED THAT THE LOWER EMERGENCY EXIT SIGN NEAR THE R2 DOOR REMAINED ILLUMINATED WITH THE SWITCH IN THE "DISARMED" POSITION. TROUBLESHOOTING REVEALED A FAULTY NR 4 EMERGENCY LIGHT BATTERY (ELPU). BATTERY WAS REPLACED IAW AMM 33-50-01 AND OPS CHECKED GOOD.