Thanks for the correction
and yes there is an S in the booking e-ticket.
FYR - I was flying from TPE-HKG then on to LHR.
I had to get my farther to book the flight but on the Cathay Pacific website with a UK credit card as I could not use my Taiwan bank card. Is that possibly why?
1. It's "Asia" Miles, not Asian.
2. The fare class usually appears between the FLT number and the date.
3. Since your FB is S3MIB (where is your origin, this doesn't look like an ex-TW FB?), the fare class is most likely "S," which is ineligible for AM.