I've had that happen too, and there's an easy way to get around it.
What's happening is you're filling too much of the lens' area with the part of the image you want to be accurate. All lens' can distort the areas near the edge of the image like this. Some worse than others, but all can do it to some degree. What you can do to fix it is to zoom back out some so that the cues are more in the middle of the image you see before you take the picture. Once the image is captured, you can crop it to show whatever you want and take away the extra area just leaving the middle where the cues are. Back when I was taking a lot of pictures I ended up with a tripod set quite a bit further back than I originally thought it needed to be. I was using a fixed 50mm lens, so I couldn't zoom. Moving it back seemed backwards to me, but it proved to be the right thing as my pictures came out much better.
Try it!
Royce