Not quite:
CX 888 HKG-JFK (1 Stop), CX 888 HKG-YVR (Non-Stop) and CX 888 YVR-JFK (Non-Stop) are actually 3 different flights and each has its own Availability.

Just when I thought I had things figured out. Are the HKG-YVR and YVR-JFK and HKG-JFK all the exact same plane? If they are, wouldn't seats booked HKG-JFK automatically affect availability on the "sub-segments"?