Installed 1×12 cedar fascia boards to a 2×8 subfascia board. I did 45 degree angle cuts on the corners. After two years the boards have started cupping and pulling away from the corners. I am wondering why it would do this? bad staining practices, wrong base of stain. or was it because my cedar board was just too wide or subfascia was not wide enough. Any ideas would be greatly appreciated. thanks