The object has separate deadzones for the X and Y axis. This means if your stick is all the way to the left (for instance) you cannot change your angle slightly by moving the stick up or down. It sticks to the 4 cardinal directions. It goes from 180 degrees to either 165 degrees or 195 degrees with nothing in between.
There is one option for disabling all deadzones for the entire object, but why make the object like this? Why not have separate expressions for raw input at least?