No, it doesn't actually but I think I see where you're getting confused. If you look at Dark down the left and Dragon along the bottom, it shows 2x effectiveness.
But if you look at Dragon down the left and Dark along the bottom there is no square there. It doesn't mean 1x effective, I just skipped all those because obviously Dark/Dragon is the same as Dragon/Dark.
I'll have a think and possibly change it so it's clearer.