Artwork error in printed map for Keep on the Borderlands

I have the printed version of the keep map in Heroes of the Borderlands Starter Set, and there is a phantom tower behind the Outer Gatehouse which shouldn't be there. I have tried to upload the image to show it exactly, but can't.

I'm sure by now it is a well- known error, but just want to know who to contact about being sent a corrected version?

The mistake I have is a round tower immediately behind the central tower of the Outer Gatehouse. It would stand on the unseen ground immediately inside the keep's entrance, before the archway in the wall running between the barn (2) and smithy (4).