Ubuntu 17.10. Windows
Worked: not found
Through some rare behavior some channels in the "map of normals" can be reversed.
Cycles ignores the map indicated in the input.
1- Open the scene.
2- Run "rendered" in the left top area. The normal map is wrong!!!
3- Click the "camera" icon in the "B" uv. (Active Render). Now you can see the normal map now, is fine!!!
4- You can delete "A" uv also.
I am suspecting that the zero map defined the map one direction...