As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
POST FLIGHT ARRIVAL AT GATE, CABIN FILLED WITH OILY SMOKE. APU WAS OPERATING AS WELL AS LEFT AIR CONDITIONING PACK. FOUND HYDRAULIC LINE LEAKING RIGHT T/R CONTROL VALVE, LOCATED IN TAIL COMPARTMENT. APU INGESTED HYDRAULIC FLUID. REPLACED HYDRAULIC LINE AND PERFORMED OPN 5088 A/C DUCT BURN-OUT PROCEDURE.