Can a Canadian traveler return to Thailand after a tourist visa if restricted by Air China waiver?

Asking for a friend, no really 😄.

So this friend is Canadian, was in Thailand for 3 months on a tourist visa. Left for China and come back for a renewal of a normal visa.

However, Air China, with which my friend has booked a return ticket ironically, have a waiver signed that the next flight is to anywhere but Thailand.

Anyone had something like this before and what do you think the chances are that the Thai immigration is aware of this and will uphold the waiver?

Or is this something from China and Air China so has nothing to do with Thailand?

Perhaps the airline would deny access to the flight from China?