Pincushioning will be found (to some extent) in most big zoom lenses.
But only at the far end of the zoom.
If you are taking pictures of drawings you had no need to be zoomed past 2X.
You may also see some barrel distortion when using no zoom (wide angle).
That is why I said previously, that you should be shooting at (or near) 50mm focal length.
Which means about 2X with that camera.
You will see no pincushioning or barrel distortion at 2X zoom.
By the way, pincushioning and barrel distortion can be removed by Photoshop and other such programs.