Steps to reproduce:
1.Download and open the attached project
2.Open scene "CubeNormals"
3.Pres play
4. Observe spinning cubes with different shaders

Expected result: second and third cubes looks the same
Actual result: second cube's normal maps are not normalized and looks different from the third cube, which was manually normalized

Reproduced on 5.2.3f1. 5.3.6p8, 5.4.2f1, 5.4.3p1, 5.5.0f2, 5.6.0a3

Notes:
the second cube's shader can be "fixed" by going to Assets/Shaders, selecting "SurfaceShader", pressing "Show generated code" and changing line 209 "o.normal = worldN" and creating a new shader by copying all the code