As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: INFLIGHT A PASSENGER DETECTED PLASTIC BURNING ODOR. JUMSEATER INSPECTED AND NOTICED SMOKE COMING FROM MID LAVATORY WATER HEATER. RETURNED TO DFW. FOUND WATER HEATER TO BE INOPERATIVE REMOVED AND REPLACED WATER HEATER PER AMM 38-12-16.