As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT THE CREW REPORTED A LAVATORY SMOKE CAUTION MESSAGE. THEN REPORTED LIGHT SMOKE IN THE CABIN AND SMOKE ODOR COMING FROM THE VENTS IN THE COCKPIT. THE FLIGHT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED ENGINE RUNS, RAN THE PACKS AND NOTED NO DEFECTS. MAINTENANCE IS UNABLE TO DUPLICATE THE CONDITION. ALL SYSTEMS CHECK GOOD AT THIS TIME.