Originally Posted by
zachfisch
I'm assuming this has to do with the fare codes and/or married segment logic but don't fully grasp what's happening here. I'd greatly appreciate further insight into this.
Yep, it's married segment logic at play, which is a form of revenue management. Qatar choose to impose a limit of available seats in certain fare buckets between certain origins and destinations. Once the city pair allocated seats are sold out then there's nothing doing unless you can persuade Customer Services to badger revenue management to open up more seats.