Of course they can fix this as they have control of both, the cube's size and the current field of view. What seems to happens here, is that by default when setting the field of view (or fov) in jPCT-AE, you are setting the fov in x-direction. The fov in y-direction is calculated from that value in a way that the aspect ratio will be maintained. Otherwise, spheres would become eggs and cubes rectangles. However, you can always disable this behaviour or choose another fov for the menu or change the size of the cube. I agree that 1024*480 is a weird aspect ratio of 32 to 15...