We've been printing on china mugs successfully for several years but suddenly have problems. The 10oz mugs we are using have a slight flared top and are Orca coated. Recent pressings have a fade toward the top edge of the print. First thought was that I was putting the mug too far into the press so the flare was affecting pressure. Test pressings eliminated that idea. Could the outer edge of the heating element in the wrap have failed? (no idea how they are "wired" inside). Thoughts or suggestions appreciated.