As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF FLIGHT CREW NOTICED ODOR IN THE CABIN, F/A REPORTED GRAY HAZE IN THE PASSENGER CABIN WITH AFT LAVATORY SMOKE DETECTOR SOUNDING. FLIGHT CREW RETURNED ACFT TO MSP. FOUND APU INLET SOAKED WITH OIL PLACED APU ON MCO. ACCOMPLISHED FULL DUCT BURN OUT IAW OPSERATION 5089 AND REPLACED COALESCER BAGS.