As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 4107 THE CREW REPORTED DIRTY SOCK OIL FUMES FROM NR 1 PACK WITH NR 1 ENGINE BLEED ON. SMELLED WORSE ON DESCENT. COULD NOT SMELL WITH APU AS BLEED SOURCE. NOTICED IN THE CABIN TOO. THE AIRCRAFT LANDED AT IAH WITHOUT INCIDENT WHERE MAINTENANCE REMOVED AND REPLACED THE NR 1 ENGINE, OPERATIONALLY TESTED WITH NO DEFECTS NOTED, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE ON 10/26/2017.