As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING OXYGEN PASSENGER OXYGEN SYSTEM (MANUAL / AUTO MODE) - FUNCTIONAL CHECK IAW GVII-G600 AMM 35-20-01, AFTER MANUALLY DEPLOYING MASKS A SOUND OF ESCAPING OXYGEN WAS HEARD. UPON PSU LOWERING IN THE AFT LH CABIN, THE OXYGEN WAS FOUND TO BE LEAKING FROM THE PSU OXYGEN BOX ASSY ABOVE THE L4 SINGLE SEAT. - L4 SINGLE SEAT PSU OXYGEN BOX ASSEMBLY TO BE REPLACED.