As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT LAV SMOKE ALARM WENT FOR ONE TO TWO MINUTES DECENDING THOUGH TWENTY THOUSAND FEET. FLIGHT ATTENDANT REPORTED NO EVEDENCE OF SMOKE OR VAPOR. REMOVED FROM SERVICE. PERFORMED GVI OF AFT LAV. NO EVEDENCE OF ANY DEFECTS. PERFORMED OPS CHECK OF AFT LAV SMOKE DETECTOR. IAW AMM TASK 26-14-01-700-801-A. OPS CHECK GOOD. RETURNED TO SERVICE.