As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FCA FLIGHT NR 2383: AFTER STARTING THE APU AND SELECTING BLEED AIR ON, A HAZE A HAZE WAS NOTICED IN THE COCKPIT AND CABIN. AFTER SHUTTING THE APU OFF, THE HAZE SLOWLY DISSIPATED. MAINTENANCE DEFERRED IAW MEL 49-00-01, RSI #349739. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.