As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: THROUGHOUT FLIGHT MAINLY CLIMB & DESCENT BURNING RUBBER ODOR REPORTED MID CABIN, APU BLEED WAS USED FOR TAKEOFF. AFTER PERFORMING SOF TROUBLESHOOTING, FOUND HEPA FILTER TO BE DIRTY, REMOVED AND REPLACED HEPA FILTER.