How to reproduce:

1. Open attached project
2. Open scene Test2.unity
3. Build scene to any platform (such as macOS)
- Note that the build succeeds, but there is an error in the console ("This MeshCollider requires the mesh to be marked as readable in order to be usable with the given transform.")
4. Using the exact same settings, build again
- Note that this time the build fails due to the same error

- A similar issue happens when using the Instantiate and Destroy buttons on the Platf_Ground-M1_Pf gameobject. If these buttons are used before a build is made, no error appears in the console. If these buttons are used after a build is made, the same error will appear each time the fbx is instantiated.

- Reproduced with 2018.1.0b1 (bcd94551ef32), 2017.1.0f2 (66e9e4bfc850), 2017.2.0f3 (253d744f3449)