As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL280 AFT LAV SMOKE DETECTOR SOUNDED WITH NO OTHER INDICATIONS OF FIRE. A/C AFT LEFT FORWARD LAV. GROUNDED - YES. DIVERSION TIME 25 MINUTES - REMOVED AND REPLACED LEFT AFT FWD LAV SMOKE DETECTOR IAW B737-800 AMM 26-14-01/401. SMOKE DETECTOR INSTALLATION TEST GOOD.