As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DSM-ATL - FLT 4756 - DURING FLIGHT, CAPTAIN REPORTED PRESSURE UNCONTROLLABLE IN AUTO AND MANUAL. CREW RESET PRESSURE AND MASKS DROPPED. AT FL100 CABIN ALTITUDE 15000 DP -2.1 TO -4.1. CABIN ALTITUDE AND DP WAS FLUCTUATING UP AND DOWN DURNIG DESCENT. AIRCRAFT LANDED SAFELY IN ATL.