maybe it is just luck
Maybe it is just luck that a week ago I tried to book 2 upgrade awards to BKK anytime in October or November and none were available on any date. Last night I booked two with the same departure and different returns at the standard level on an "M" fare. I am platinum, the other traveler is gold.
The advice to keep trying is IMO the best one. Seats do get released. The new computer system seems to make it much more difficult to book in some ways and much easier in others. These tickets were booked on July 7 for an October 5 departure.