As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH AUXILIARY POWER UNIT RUNNING AND BLEEDS ON, SMOKE IN CABIN AND LAVATORY SMOKE DETECTOR SOUNDS. RAN AUXILIARY POWER UNIT WITH BLEED ON, VISIBLE HAZE APPEARS. INSP AUXILIARY POWER UNIT AREA NO DEFECTS NOTED. RAN ENGINES WITH BLEEDS NO HAZE NOTED. R&R AUXILIARY POWER UNIT PER WORK CARD 49-20-02X OPS CHECK GOOD. NO SMOKE FROM APU BLEEDS.