As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALT WARN ANNUNCIATOR PASSING 12K, CABIN PRESSURE WAS 12K. PAX. 02 MASK DROPPED. UNABLE TO CONTROL CABIN ALTITUDE BELOW FLIGHT ALTITUDE. THE PRESSURE CONTROLLER WAS THE CAUSE. PRESSURE CONTROLLER WAS REPLACED. NO FURTHER ACTION REQUIRED.