Hi AG, there are hundreds of stories around regarding TG this week, all juicy, but to add to this puzzle, the First class to SYD has been on deep discount in Bangkok since day 1, until yesterday. I wouldn't read too much into that as they are gearing up for something else.
However to follow Sydfly's thread further, when I tried to buy F ticket on awards for March April and May, there were at least 2 seats available on many dates. I then tried 31st March and there was availability for at least 2 tickets in First, Business and economy on TG 451 and Tg 457. TG455 was available only in economy.

Trust all this has confused both of you even more, if I have time later I will follow up. my thoughts are is that ANA is faulty, and that TG have a habit of showing the 2 centre seats as being sold