Date: 201912
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Aircraft component: Oxygen System/Pax
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Human factors: Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Passenger
When detected: In-flight
Result: Flight Crew Diverted; General Maintenance Action
Contributing factors: Procedure
Primary problem: Procedure

Narrative: Aircraft was ferried from ZZZ to ZZZ1 and a flight test of a mechanical issue was accomplished on that flight; by I am assuming company test pilots.Aircraft preflight was normal and departure was normal until two ECAMs for an emergency exit door being open. QRH was run and aircraft pressurization was normal so flight was continued. Probably 10 minutes later an ECAM for an inoperative TCAS was experienced and run. ATC was notified that the TCAS was now inoperative. About 1 hour into the flight; we received a call from the flight attendants that a passenger noticed a 'placard' on the oxygen mask cover above row 25DEF that said 'Oxygen Canister Needed'. With no way to verify that the canister was in place or not; and with three open seats; we elected to move the passengers from that row to ensure they had oxygen available. During the process of moving them; it was discovered that row 23DEF had the same placard which turned out to be tape with the same wording on it.Now; we were in the position of potentially not having enough oxygen for the passengers in the event of a depressurization. I gave the aircraft and the radios to the FO (First Officer) and had him begin a controlled descent to 10;000 feet. I got a phone patch to dispatch and Maintenance Control. We discussed the situation and agreed that the proper and safe course of action was to stay at 10;000 feet and have the aircraft go to destination that the canisters could be verified to be; or not be in place. ZZZ2 was the agreed to destination since we doubted the ability of the aircraft to be able to get to the destination or back to ZZZ1 which was slightly closer at the time; at 10;000 feet.After the phone patch was over; and we had turned the aircraft towards ZZZ2 the Dispatcher sent a message saying we could arrive at ZZZ3 with 4.7 on the fuel. We were already heading back north; and 4.7 with an airplane that had already had a couple of spurious ECAMs and now had us doubting the safety of the aircraft maintenance inspections; led us to reject that option. We continued towards ZZZ2.As we were heading towards ZZZ2 it occurred to me that ZZZ1 was slightly closer and might give us the option of arriving about a comfort level of 5.0 on the fuel; and would give company maintenance the opportunity to inspect the aircraft and to give our passengers better routing options in case the canisters were not in place. The Dispatcher's initial run on system gave us 5.2 at ZZZ1; so we changed the destination to ZZZ1.After putting ZZZ1 in as the destination and with a direct ZZZ1 routing and a two fix approach for Runway XXC in the box; the fuel at ZZZ1 was 3.8 varying to as much as 4.1. This was not what the flight plan Dispatch sent us had. We did the basic math of time remaining times fuel flow and that agreed with what the box was telling us. Neither of us on the flight deck were comfortable with putting ourselves into a potential minimum fuel situation when we had just passed a perfectly good airport less than 40 miles away. I made a command decision to yet again go to ZZZ2. Dispatch was notified and we landed uneventfully in ZZZ2 with 7.0 approximately in the tanks.Upon arrival in ZZZ2; the passengers were deplaned and the suspect mask covers were dropped and found to have canisters installed despite the masking tape placards saying otherwise.The rest of the maintenance items were taken care of in ZZZ2 and the passengers were re-boarded and we departed ZZZ2 and completed the rest of the flight uneventfully.The Dispatcher and I spoke on the ground in ZZZ2 about the fuel discrepancy. The flight plans he sent us all had us going above 10;000 on the way to ZZZ1 and that clearly led to more fuel remaining than was really going to be there. He also said that he was struggling to get system to give a direct routing; but after the fact he was able to get a flight plan that confirmed the 4.2 or so in ZZZ1 that we and the box had come up with.




Synopsis: A320 Captain reported that a cabin placard indicated several passenger oxygen masks may have been inoperative; resulting in an expedited descent and diversion.