As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH THE EQUIPMENT COOLING SWITCH IN OVRD POSITION & BOTH PACKS OPERATING AT 39,000 FEET, THE CABIN ALTITUDE CLIMBED TO 11,000 FEET. THE FLIGHT CREW DESCENDED TO 10,000 FEET TO REGAIN PRESSURIZATION. REPLACED THE COUPLING & SEAL THAT JOINS THE CONDITIONED AIR GND CONNECTOR TO THE ADJACENT T DUCT. THE CAUSE OF THE CABIN ALTITUDE CLIMB WAS THE FAILED COUPLING ABOVE THE CONDITIONED AIR GND CONNECTOR.