It's a new P3D bug. It seems that taxiway paths of the "vehicle" type are always drawn, even if the "drawSurface" flag (which P3D is supposed to honor) is set to FALSE.
We'll report it to LM, because it's surely not a correct behaviour.
In the meantime, if you reinstall KDFW now, and reply YES to the question of downloading the latest AFCAD, we put an updated file that will side-step the problem.