Actually I find something very strange within CX booking system as well! (maybe some of you discussed it before)
When I try to search for HAM-HKG J class fare, on CX website, obviously they offer either transfer at DUS with AB connection or LHR with BA connection. But when I do the same search on CX mobile app, more options like LH and KL are available(some kind of old agreements before AB joined Oneworld?), and no J class option available for ordinary AB/BA connection options! How strange is it??