I tried to make a dummy booking without FFP (HKG-TYO r/t) and could see the hold booking button right next to "pay now" at the final stage. With CXGO you should now be able to hold 72hrs for free if you are one of the travellers.
Per
https://www.cathaypacific.com/cx/en_...your-fare.html,
- This feature is not applicable for departures from China, India and Canada. (this limitation exclude for Marco Polo Club member’s booking)
- This feature is not available for flights departing within seven days (168 hours).
- Please note that Hold Your Fare will not be available if your itinerary includes a flight number of another airline, i.e. begin with any other code other than 'CX' or 'KA'.
So either it did not recognise the FFP, the flight is close to departure, or involves partner.