From my past exeprience, it seems like that CX "zeros" out all of their inventory for a flight a few hours before check-in opens.
For example, on my JFK-HKG flight on CX 889, it was showing F4 A4 J4 etc. the day before departure, but on the day of departure it showed F0 A0 J0 etc.
When I actually boarded the flight, there was only 1 other passenger in F.