I have a blender scene with a plane displaced with noise to make mountains and water. I used a mask to separate the water texture from the mountains. It is not finished, but there is this weird line across the image whenever I look through rendered view where the texture seems to become lighter. Even weirder, it moves when I move the camera up and down, or when I move the mesh. I tried both CPU and GPU rendering. I have attached some pictures, and would really appreciate any help anyone can give.