i would have thought that the flat bits of the normal map would have normals facing straight up and so would be the same as other parts of the object that are flat shaded… see video
A couple of things to note, the normal map image texture needs to be set to non colour (colour space), you should also use a normal map node to plug it in.
Thanks, that was the problem. Only seems to work when the image i am using is an external file for me though. Not a problem though.
That is because when you baked the image you baked it to an image that had RGB set as colour space. If you do not save the image the colour space will be greyed out.
As soon as you save the image externally (or pack it into the Blend file which saves it inside the Blend file) you should be able to change the colour space again.
Another way of doing it is to duplicate the image node and hit the user number button to make the copy single user. you can than change the colour space of the copy and delete the original node.