As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT LAVATORY SMOKE WARNING DURING FLIGHT, PERFORMED VISUAL INPECTION OF AFT LAVATORY, NO SMOKE DETECTED, AIRPORT CFR REPORTED NO EVIDENCE OF SMOKE OR FIRE IN LAVATORY. PERFORMED OPS CHECK OF LAVATORY SMOKE SYSTEM IAW AMM 26-16-00. OPS CHECKED GOOD. THE SMOKE WAS CAUSED DUE TO THE PRESSURIZATION FLUCTUATION. REMOVED AND REPLACED CABIN PRESSURE ALTITUDE PANEL IAW AMM 21-33-01710-801. OPS CHECKED GOOD IAW AML 4020827 ITEM 2.