As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PERFORMING EMERGENCY EVACUATION SLIDE OPERATIONAL CHECK, THE SLIDE INFLATED AS IT SHOULD BUT THE EMERGENCY LIGHTS DID NOT TURN ON. FOUND ONE OF THE LANYARDS ON THE BATTERY SUPPLY LOOSE, AND AS A RESULT THE PLUG TO ACTIVATE THE LIGHTS DID NOT COME OUT. RECONNECTED LANYARD.