When i tried to bake normal map(high poly / low poly cube) to a cube and I got some strange artifacts. I’ve changed specular shader to WardIso just to make artifacts better visible.
Im attaching blend file for further investigation. High poly on layer 1, low poly on layer 2. Both layers must be visible when baking, and normal map texture checkbox must be unchecked on textures tab before baking (if not bake will produce wrong texture).
tangent_normals.blend (1.28 MB)