As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON APPROACH, LAVATORY SMOKE CAUTION APPEARED ON EICAS AFTER TRANSFERING BLEEDS FROM ENGINE TO APU. FLIGHT ATTENDENT ALSO REPORTED SMOKE IN CABIN AFT OF ROW 10. INSP LAVATORY FIRE DETECTOR AND FOUND IT HAD NOT DISCHARGED. PERFORMED OPERATIONAL TEST OF APU AND ACM. NO OTHER DEFECTS NOTED, ACFT RETURNED TO SERVICE.