As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK ON DESCENT INCREASED TO 90 DEGREES AND SMOKE WAS EXHAUSTING BRIEFLY INTO THE CABIN WITH A SMELL. REDUCING MANUALLY TO 50 DEGREES STOPPED SMOKE. MTC ATL NOTIFIED IN FLIGHT. REMAINDER OF FLIGHT NORMAL. RAN LEFT PACK IN AUTO AND MANUAL THROUGH FULL TEMP RANGES. ALL INDICATIONS NORMAL. NO SMELL OR SMOKE IN CABIN. REPLACED CABIN TEMP CONTOLLER AS PRECAUTION. OPS CKS GOOD.