I believe HKG currently has strict restrictions on transits? I believe you're not allowed to change airlines, which means you can only fly CX all the way, basically?

It's currently only extended through April, but I still think that has something to do with it:
https://www.cathaypacific.com/cx/en_...formation.html

Probaby the airlines don't want to take the risk of having to rebook people at the moment, so they simply don't offer such tickets.