As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT LAVATORY SMOKE MASTER WARNING. MOMENTARALY. POSSIBLE PAX WITH VAPE, UPON MX ARRIVAL DEBRIEFED BY CAPTAIN AND F/A CREW CONFIRMATION OF PAX IN LAVATORY F AND SMELLED AN MARIJUANA ODOR WHEN EXITING THE LAVATORY. INSPECTED LAVATORY F NO EVIDENCE OF TAMPERING NOR ODOR REMAINED. IAW AMM. 05-51-10. OPS TEST OF LAVATORY SMOKE WARNING DETECTION SYS REF AMM 26-17-00. OPS CHECKED GOOD.