so, I just moved to 2.8 a few days ago and have this texture problem with Eevee. Whenever I use a normal map the light does not hit the texture in a diagonal way and there is a diagonal shadow with it. This only happens when I use a normal map on an object (with and without color map) using Eevee. On Cycles I have no problems. I tried a different texture from a different source and the same problem occurs. Is this a bug? Or am I doing something wrong?
How can i fix this?
I’m not sure what you mean here. Can you clarify what you are trying to do and what is the problem? Also make sure normal and roughness maps color space is set to Non-Color.
ok, so i am expecting the light to distribute in all direction since it is just a simple point light.
But what i get is this one sided light. The light does not pass through the white line i marked, and a shadow appears on the black lines, i am not sure why this is happening
I will later include more examples once i am home.
Change the color space of your normal map ( image texture node) and roughness map to non-color, this should make things better.
Basically all image textures which are not used to inform a yellow color socket should be set to non-color.
I’m also wondering if your plane has smooth or flat shading. Flat shading should be used for a plane to prevent shading problems.
Yeah, set to non-color. When using a color space, the value 0.5,0.5 indicating a flat surface gets modified, and the normal modification tells the surface to shade as if it was at an angle.
You know you have in the menu “Window/Save Screenshot”, right? 
In the last image you cropped away what we would be looking for.
Okay thanks, setting it to non-color fixed the problem. I am honestly embarrassed i forgot that xD. Again thanks for the help guys.
Problem fixed, thanks.
(No i didn’t know about the “Window/Save Screenshot”) 
It also happens to me from time to time, but I learned to recognize and remember the source of the problem 
