As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE IN MID CABIN REPORTED BY FLIGHT ATTENDANT. DISCONNECTED PIG TAIL AND ISOLATED. SMOKE AND ORDER DISSIPATED. SUPPLEMENTAL DATA UPDATE CART HEATER PIG TAIL OVERHEATED WITH EVIDENCE OF BLACK CHARRING. CART HEATER PIG TAIL WAS REPLACED, CART HEATER OPERATIONALLY CHECKED GOOD. NO FURTHER INCIDENCES.