Well, they probably had to remove the wiper arms in order to replace the windshield. When they put the arms back on, they probably replaced the driver's side arm a spline or two off from where it should have been, so it now contacts the windshield molding when the wiper is at its highest position. Same thing happened when my dad's S-10 pickup was repainted under paint recall at the Chevy dealer. I'd take it back to them and make them fix it.