As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#1673, JFK-BNA.' IN CRUISE FLT LVL 340 RECEIVED LAV SMOKE EICAS WARNING QRH COMPLIED WITH NO SMOKE PRESENT MSG DISAPPEARED AFTER 5 SECONDS. FA SAID THE PREGNANT LADY IN FWD LAV WAS TAKING A POOP AND NO SMOKE WHEN MSG APPEARED. AFT LAV WAS NO OCCUPIED ( LAV SMOKE DETECTION SYS ); REMOVED AND REPLACED FWD LAV SMK DET. PER AMM 26-14-01 OPS CHECK WAS GOOD. CLEARS MDDR. MX -4 UPDATED. PLACARD REMOVED.'