Landscape is deformed on Mobile preview

1. create any template project
2. change to landscape edit mode (Shift+2)
3. check import from file
4. select height map to attached Heightmap.png file
5. click import button
6. change to landscape select mode (Shift+1)
7. change to wireframe mode (ALt+2)
8. change to Android ES 3.1 preview (Setting > Preview Rendering Level > Android ES 3.1)

Expected : Landscape is should be identical

Actual : Landscape is slightly deformed on mobile preview