Why would my mosfet driver output 1v when not triggered?
When driving MOSFETS with Micros. It is important (but not often mentioned) to use a pull-down resistor on a NPN type MOSFET (or Pull-up on a PNP type mosfet). To prevent your Gate from floating!

Note that the Gate acts as a small capacitor and stores some charge causing the MOSFET to 'float'. You use the 10K resistor from Gate to Ground as an anchor to ensure the Gate drains to 0v when not being driven.