The brush preview/cursor is larger than what is actually drawn

I have a pen tablet but I've disabled any pressure or tilt settings. When I hover over the canvas with the brush tool, there is a circle with a crosshair in it to preview what will be drawn, and this circle scales with the brush size. However, it is always much larger than what is actually painted, as shown in the photo. I'm guessing this is not intended, so does anyone know how to fix this?