After several years of use, the plates on my Cuisinart Griddler have warped. I always check to make sure they are installed correctly prior to use. The center of the places have warped away from the heating surface to the point that they are severely bowed and are no longer fit tightly in the clamps. Why did this happen? We often take the plates out of the grill while still hot so the grease does not burn on and they are easier to clean.