As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: SOF EVENT DURING DESCENT PASSING 25000 AND IDLE/LOW THRUST DESCENT. FAS REPORTED SMELL AS WELL. FUMES PREVALENT THROUGH MAJORITYOF DESCENT. OILY SMELL IN FLIGHT DECK AND SOUR MILK SMELL IN AFT CABIN. MAINTENANCE FOUND APU INLET SOAKED IN OIL. REPLACED APU IAW J/C 26L31049003.