As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON DESCENT AS WE LEVELED AT 6000' AND THE POWER INCREASED THERE WAS A DIRTY SOCK ODOR THAT LASTED ABOUT 1-2 MINUTES. THE ODOR WAS NOTICED IN BOTH THE CABIN AND THE FLIGHT DECK. THE ODOR DISSIPATED AFTER THE POWER DECREASED ON RESUMPTION OF DESCENT. APU WAS OFF. ODOR STILL NOTICEABLE AT GATE AFTER APU BLEED TURNED ON. MAINTENANCE FOUND THE HEPA FILTER DIRTY AND REPLACED IT PER AMM 21-21-41.