As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RECEIVED LAVATORY SMOKE WARNING SHORTLY AFTER TAKEOFF, GEAR RETRACTION. UPON INSPECTION FOUND NO TRACES OF FIRE OR SMOKE. SUSPECT FAULTY LAVATORY SMOKE DETECTOR. R & R SMOKE DETECTOR SENSOR IAW AMM 26-14-01. OPERATIONS CHECKED GOOD. NO SMOKE DETECTED AT THE TIME.