Couple reasons.Why not just let it dry before putting it up??
There's a mill in Louisiana who does it right and the only other one I know of is near Gainesville Fl, they claim they can kiln dry it but I haven't bought any only their air dried. It's not problems with cypress its just extremely wet and a bit unstable to start with... after all it is a fern.Kiln drying can be done if it is done right. I haven't really heard of so many problems with cypress. I know many times it is put up green though. And I realize some boards behave worse than others.