Thai (TG) would not allow me to book United flights to & from Houston to connect to my trans-Pacific ANA (NH) flight to Tokyo.
They said the trip was "too long." I don't know if was related to this TG-UA problem or if TG limits Star Awards to three (3) segments in each direction.

I am happy that I was using up the Thai miles this year rather than the United miles because at least I was able to book a TG & NH first class round trip.

Even if they allowed me to book the flights to & from Houston the UA flights would have been in coach to connnect to a first class flight to NRT.

Remember the days when Continental would open up the domestic first class inventory if you were booking a business or first class international award?