As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, NR 2 PACK VALVE INDICATES OPEN WHEN SELECTED CLOSED. VALVE CURRENTLY ON MEL. ALSO RECIRC CAN BE SELECTED TO RECIRC WITH ONLY 1 PACK RUNNING. A LOUD POPPING SOUND FROM REAR OF A/C. AIR RETURN TO MSP. MAINTENANCE REMOVED AND REPLACED PERI-SEALS ON NR 2 PACK VALVE (P/N 706-3-250). OPS CHECK AND LEAK CHECK GOOD.