As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW O2 WENT TO 60 PSI DURING FLT CAPTS O2 MASK MADE A GASPING SOUND. DIVERTED TO YYT FOR REPAIR. AIR CANADA EQ AMTS SERVICED CREW O2 AND ISOLATED LEAK TO CAPTS MASK. SWAPPED WITH 2ND OBS MASK AND FWD 2 OBS O2 MASK TO MCO PER MEL 25-11-02B.