As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: SLIGHT DIRTY SOCK ODOR ON APPROACH. NO MASKS USED. FA DID NOT NOTICE ONLY PILOTS SMELLING IT. ACCOMPLISHED WORKCARD 26L00021001. FOUND ODOR COMING FROM RECIRCULATION SYSTEM. RECIRCULATION FILTERS REMOVED AND REPLACED PER AMM 21-21-41. NO OIL FOUND IN APU INTAKE OR COMPARTMENT. NO ODER NOTED FROM ENGINES OR APU. OK FOR SERVICE.