Terrain and Light Problem: Only half of the radius of point light and spotlight touch/cast the terrain

*Please see the attached image, the image itself can explain my question.
I have two light, which is point light and spotlight. Both of them are set in important, has a soft shadow type, and Baking is set to realtime.

For this problem I tried to solve it using the knowledge I get from other forums. So here are the following things I tweak:

  1. I changed the value of Pixel Light Count, I put it on “10” (still have the problem).
  2. I tried to play with rendering path, forward rendering and deferred rendering (this isn’t solve my problem).
  3. I also increased the “Scale in Lightmap” to “128” (nothing happened).
  4. Tried to play with Color Space, linear and gamma but I still have the problem.

here is the link:
https://drive.google.com/file/d/0B1vRoOkOP-y8bTJHOThkMnBiMTA/view?usp=sharing

I hope you can help me, thanks in advance!

Vertex normals in your terrain is what is causing this problem.

By looking at your video it seems that normals are rotated 90 degrees (probably either x or z axis is swapped with the y axis).

It might be a problem with the normal maps you’re using, or even how you are importing them into Unity.

I also am experiencing this issue, has anyone found the resolution? logged a bug with Unity?

Check your normal map and make sure the texture type is set to “Normal Map” mode instead of “Default”
81894-normal-issue.png