As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING NON PRESSURIZED FLIGHT WHILE AT 10,000 FEET THE PASSENGER CABIN OXYGEN MASKS DEPLOYED. MAINTENANCE ACTION FOUND OXYGEN REGULATOR HAD FAILED. OXYGEN REGULATOR REPLACED AND LEAK CHECK CARRIED OUT. TEST CHECKED SERVICEABLE AND OXYGEN MASKS RESTOWED.