As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER TAKEOFF, THE LAVATORY SMOKE DETECTORS WERE ACTIVATED BY SMOKE ENTERING THE CABIN FROM THE AIR CONDITIONING SYSTEM. THE FLIGHT RETURNED TO ATL AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT AND CHANGED THE AIR CONDITIONING COALESCER BAGS. NO OTHER DISCREPANCIES NOTED.