I don’t get this. I’m a travel agent, but admittedly a new one, and class availability is class availability. If I ask my gds to take 2 seats from D with my POS and destination, it will take them, and the airline will sell them if there’s a fare listed.

Now clearly there is a fare, but the issue is that one GDS/company is seeing D and the other isn’t. This discrepancy is the issue. It could be a point of sale issue, or married segment, but it’s worth asking the question- why the difference. This helps plan your xONEy in the future.