i would try to things.
first one are the options in the blue square, as far as i know these are the only options that allow you to turn of materils and maping off when rendering.
second is the green squares in the materil editor, click the ball with an arrow goin to it (the green square) it will bring up the window to the right then click "scene" (green box again) this will show all the materials in teh sence even if they are not on the material editor, just drag across the materal you want to a new materal ball and see if that works.
if the dont work i am thinking max is stuffing up, i cnat think of anyhting else that could do that.