As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING EMERGENCY LIGHTING SYSTEM TEST, A EMERGENCY LEFT EMERGENCY POWER SUPPLY INTERNAL LOAD FAULT MESSAGE DISPLAYED. MAINTENANCE FOUND INOPERATIVE BULBS ON THE MID CABIN FORWARD-FACING EXIT SIGN AND REPLACED THEM. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.