After importing "The Courtyard" project, textures are missing until material shaders are set to "Standard"

1. What happened

After importing "The Courtyard" project, most textures are missing until material shaders are set to "Standard".

2. How we can reproduce it using the example you attached

- Download and import "The Courtyard" project from the Asset Store;
- Open the Courtyard scene;
- Notice that almost all textures seem to be missing.

Note: Seems like similar issue as case 790496.
Note2: Setting the shaders for buggy materials to Standard/Standard (Specular setup) makes objects appear normal.