As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FO OXYGEN MASK PUSH TO TEST SWITCH BROKEN. SWAPPED FO O2 MASK AND BOX WITH 3RD OBS SEAT PER MEL 25-11-06A M PROCEDURES C/ W PLACARD INSTALLED. R & R FLIGHT CREW MASK STOWGE BOX IAW AMM 35-12 MEL CLEARED PLACARD REMOVED A/C OK FROR SERVACE. (LP: 6791268, AIRCRAFT WAS GROUNDED)