As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 4377 BNA/MEM - AT THE GATE WHEN BLEEDS WHERE TURNED ON CREW RECEIVED "LAV SMOKE" WARNING WITH VISIBLE SMOKE IN THE LAV AREA. MAINTENANCE INSPECTED AND FOUND THE APU TO BE LEAKING OIL CAUSING THE SMOKE. APU WAS DEFERRED PER MEL 49-10-11.