I'm wondering if you place a straight edge along the length of the track, do you see the window frame bow outward in reference to the straight edge? If so, a couple things come to mind. The first less likely is that the frame could be bowing outward due to a lack of a header placing too much weight on the top of the window frame. The second, more likely scenario I think, is that there are no shims on the middle of the sides of the window frame between it and the jack stud and the window frames spread slightly outward. Both, in my opinion from many miles away
, are installation errors rather than manufacturing errors. The mfg rep should look at it and be able to tell you that and then get the builder to fix it. You will probably need to take off the inside trim pieces on the sides of the window to see for sure.
There should be insulation stuffed in this space between the frame and jack stud which also helps keep the frame from bowing outward. When installing this insulation, you must be careful not to stuff too much or it forces the frames inward and makes the windows too tight to open and close.
If the window jamb is straight then it leads toward a mfg defect with the window between the sash and track.
I hope for your sake the shims would fix the issue. I would be easy enough to try it on a window to see the effect.
Like the Pella's mentioned earlier, our Andersen's installed between 7 and 15 years ago have no draft at all.