GE Z Wave Dimmer Paddle Doing the Opposite of What It's Supposed To

That device has a parameter which allows you to reverse top and bottom, so that’s probably the easiest. (Usually used by people who install it upside down, but it seems likely that the parameter’s just been sent wrong on your device. ) it’s called “invert switch“ and if I remember correctly, it’s parameter four.

Anyway, if when you look at the device details in the SmartThings app there’s a little gear icon and you open that it should allow you to set the parameter to reverse the top and bottom.

If the particular DTH you are using doesn’t have that, you can temporarily assigned the switch to the Z wave tweaker, change the parameter, save it, and then switch back to your every day DTH.