Reproduction steps:
1. Download the attached "Stripped" project.
2. Open it with 4.7.2.
3. Open the "Stages/_Stage0a1 on the farm" scene.
4. Focus(double click) the "Barrel" game object.
5. Notice that it is visible("Visible" screenshot).
6. Repeat steps 2-4 in Unity 5.
7. Notice, that the object is invisible("Invisible" screenshot).

Notes:
- It works if scene is exported and imported into another project(4.7.2).
- It also breaks, if library is deleted(4.7.2).
- Attempted to fix scripting errors, but meshes are still invisible in Unity 5 when no errors are present.

Reproduced with: 5.2.5f1, 5.4.5p1, 5.5.3p2, 5.6.0a3
Not reproducible with: 4.7.2
Regression introduced in: Unity 5 ( I could look for a more accurate version, just poke me on slack )

Reoslution:
Unity requires maya to be installed in order to convert maya meshes to fbx. There's an error message in the Unity console saying stating that "Maya was not found."