Booked a trip to Shanghai on J this September. After booking...I was surprised that they were not using the regional 773 instead my booking said 77A. I got curious and wanted to check how much is the difference to fly F instead. But when I tried making a new booking in F (it's about 1,300 vs 788...too much if you ask me) I was surprised to find that the PVG-HKG flight has a yellow star beside it which means its on business class instead.

So when I checked the seat reservation on my J booking I saw that rows 1&2 appeared on screen albeit marked with an "X" which mean its either blocked or occupied.

Any thoughts?