OP - have your profile details with the airline changed in any way (even minor like added Mr.)? The smurf person matching engine is quite anal about all the i's & t's being exactly the same every single time.
I've had similar experiences... book a ticket directly with the airline and hardly get any love; but book with my corporate TA and got loved almost every time. And all this because the airline profile has my name listed as "Mr. Jupiter Ally" while the corporate TA uses "Jupiter Ally"