As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB EICAS AMBER CAS MESSAGE "CABIN ALTITUDE" ILLUMINATED. THE PRESSURIZATION SYSTEM WAS PLACED ON MEL AND FLOWN TO MAINTENANCE IN KOAK. ONCE IN MAINTENANCE THE PRESSURIZATION WAS TESTED AND THE DEFECT COULD NOT BE DUPLICATED. ALL COMPONENTS OF THE SYSTEM WERE FOUND TO BE OPERATING AS NORMAL. AIRCRAFT WAS RETURNED TO SERVICE.