As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT THEY RECEIVED A LAVATORY SMOKE INDICATION AFTER TAKE-OFF. CREW ALSO REPORTED THAT THERE WAS NO SMOKE OR ODOR PRESENT IN THE CABIN OR COCKPIT AND THE MESSAGE CLEARED BEFORE LANDING. THE AIRCRAFT RETURNED TO FIELD AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS FERRIED TO SDF. MAINTENANCE FOUND THE ENGINE 2 ZERO CARBON SEAL TO BE LEAKING. THE CARBON SEAL WAS REPLACED. OPERATIONAL AND LEAK CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.