Is this something you have created with Photoshop and then exported as a PDF? If so you need to remove the layer (or just hide it) before exporting as a PDF. This KDP overlay is just here to serve as guidelines for the creation, and should be discarded prior to exporting.
If you want to show us your layer stack within Photoshop, I can tell you which one to remove.
If it was done with another software than Photoshop, let me know and I'll move your post to the correct place.