Oh, that explains it. BKK-MNL today, at check in agent wanted me to pay THB990. Told her I selected this seat in advance, and there was no charge notification on the site (would have selected something else, and in fact still might as someone else is in the middle seat). She had to call supervisor to OK it.

On the same booking on another flight they moved me out of pre-selected seat due to "electronic device malfunction" (what does that even mean? no TV? on a 1 hr CNX-BKK flight?). Serves me right for using miles to fly TG when I should have paid to fly AirAsia.

P.S. The "electronic device malfunction" was a family or friends of the crew. Guess I had the only almost empty middle row