As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE POST FLIGHT CHECKS, THE FLIGHT CREW REPORTED A HISSING NOISE COMING FROM UNDER THE INSTRUMENT PANEL, CORRESPONDING TO THE OXYGEN GAUGE GOING DOWN. DISCOVERED THAT THE OXYGEN CAPILLARY LINE HAD BEEN CHAFED BY A REMOVABLE INSPECTION PANEL. A NEW LINE WAS INSTALLED AND POSITIONED TO CLEAR PANEL.