As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5992 HOT TO YUL - DURING CRUISE, THE CREW RECEIVED A MASTER CAUTION FOR LEFT PACK HIGH PRESSURE. THE FLIGHT DIVERTED TO SDF AND LANDED WITHOUT INCIDENT. MAINTENANCE WAS CALLED OUT TO THE AIRCRAFT AND THE PRESSURIZATION SYSTEM WAS OPS CHECKED IN ACCORDANCE WITH AMM 21-31-00 ON ENGINE AND APU BLEED AIR, WITH NO FAULTS FOUND. THERE WERE NO CMC MESSAGES PRESENT. THE PACKS WERE INSPECTED WITH NO DEFECTS NOTED AND THE AIRCRAFT WAS RELEASED TO SERVICE.