As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SAT INFLIGHT T620/21SEP. CREW REPORTED SMOKE IN CABIN WITH HEAVY SMOKE IN AFT CABIN DURING CLIMB. RETURNED TO SAT AND LANDED WITHOUT INCIDENT. UPON LANDING SMOKE DISSIPATED. FOUND RESIDUAL OIL FROM OVERNIGHT APU WORK. REPLACED BOTH COALESCER BAGS AND ACCOMPLISHED PACK BURN. SYSTEM GROUND CHECKED NORMAL OPS.