As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE AT 45,000 FEET, THE PILOT REPORTED THAT THE CABIN ALT CLIMBED TO 22 000 FT, OXYGEN MASKS DEPLOYED AND AN EMERGENCY DESCENT WAS CARRIED OUT. WAITING MORE INFO FROM CUSTOMER. THE MFG HAS INSPECTED THE VALVES AND THEY CONCLUDE THE VALVES WERE (NO FAULT FOUND). THE INVESTIGATION IS ONGOING. (TC NR 20080213005)