As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING LEVEL FLIGHT FL360, AFT RIGHT, LAVATORY E, SMOKE DETECTOR WENT OFF FOLLOWED BY A LAVATORY SMOKE LIGHT INDICATION IN COCKPIT. PASSENGER MIGHT OF BEEN VAPING. NO SMOKE OR FUMES DETECTED. SMOKE LIGHT DISPLAYED FOR 3 TO 5 SECONDS, TWICE. MAINTENANCE PERFORMED SATISFACTORY OPERATIONAL CHECK OF RIGHT AFT LAVATORY SMOKE DETECTOR SYSTEM PER AMM 26-14-00.