I actually experienced something similar before - trying to get award seats on intra-Asia AY flights with AAdvantage miles...the HKG AA agents basically said there's no award availability on any intra-Asia AY flights, no matter what class I want or what date I pick...they just cannot see any availability / I cannot use any intra-Asia AY flights as part of any AA awards at all. (for example I was trying to get HKG-BKK on CX and BKK-HKG on AY - on dates where AY were flying - but award not possible at all).

Would appreciate some expert opinion on this as well...I always have been thinking if it's just a system glitch (e.g. in AAdvantage's system they didn't list AY as one of the airlines flying within Asia), but I just didn't have time to investigate yet...thanks a lot.