As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREFLIGHT, DISCOVERED FO O2 MASK BOOM MIC INOP. SWAPPED FO WITH 4TH OCCUPANT SEAT MASK PER A319 AMM 35-12. DEFERRED 4TH OCCUPANT SEAT TO MEL 25-11-07. M PROCEDURES C/W AND PLACARD INSTALLED. R & R F/O MASK BOOM MIC IAW AMM 35-13. OPS/LEAK CHECK GOOD. RFID UPDATED, SWAPPED PROCEDURE REVERESED. PLACARD REMOVED. (LP: 8847386, AIRCRAFT WAS GROUNDED)