I found the reason we have had problems with our rear day/night shade from day 1.
It only has two screws in it for support, one on each end..it's 6' long, the center sags about an inch. This causes all kind of operational problems. Our tore on the top on one end, I'm on the way over to get our replacement now.
Here are some pictures of the shade, didn't turn out real good, but you can imagine the heavy shades supported by one screw on each end.
The pictures are grouped in with cable from another post.
It works better if you choose slide show and change the interval to 6 seconds.
Camera cable and rear shade pictures