Gradient not displaying properly / not copying properly.

So basically, the bottom and top gradients here are the same. Both set at 270 degrees with a fountain fill from black to white (which is straight up and down)

As you can see, not only is the gradient different at its end points with a darker white and lighter black at the ends but also the top curve (the copied one) has much darker black near the centre of the bottom than the edges, considering that this is a straight up and down gradient I don't see how it can give me a black with such varying horizontal intensity.

Any insight as to why it's doing this would be appreciated.