Critical issue with glitching standard shaders

Hi!

We faced a critical problem with one of the final builds of the game which we are developing and preparing for the release.

So, describing our problem in details we are using unity 5.6.3f1 and buildng our game for VR platforms. When we build our game some static meshes with standard shader start to look like they were unwapped for the light mapping while dynamic objects get a lot of black dots over the texture:

When we faced that trouble for the first time deleting of the library folder and reimpording of all assets (nearly 100GB..) helped, but now it doesn't work at all.