While the above remark can apply to SQ (dunno about EK, no recent experience with them), in this case I would say that common sense dictates prudence on part of the airline. Just because OP has gotten through Chinese immigration on numerous occasions on an APEC card that is no longer linked to his current valid passport, is no guarantee that this will continue. Especially so if it is an aberration or even contravening of regs. If some Chinese immigration officer decides one day to be an ... (or go by the book), OP'll be in a jam and so would the airline concerned. Unless, for some reason (unlikely) China's regs for ABTC are more relaxed.