As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK - AFT GALLEY, SMOKEY HAZE IN CABIN AND ODOR OF ELECTRICAL BURNING. AFTER QRH COMPLETED DOWN TO RIGHT PACK OFF, SMOKE DISSIPATED. LEFT PACK WAS NOT TURNED OFF. REMOVED AND REPLACED RIGHT ACM & CABIN HEPA FILTER PER MM. AND RIGHT WATER SEPARATOR SOCK PER M/M.