Imported Terrain Details are black

Hello, In the process of working on a project, I have reached the point where I need to export a scene (and all dependencies) as a package. While this works fine, when importing said package into a NEW project, all of the terrain details (bushes, etc.) are entirely black, and very distorted.

I have no idea what has caused this. The package exports without error, it imports without error, and all of this is being done on the same desktop (windows 7 x64) on the most up-to-date version of Unity.

Fixed it:
I deleted the terrain and detail meshes from the project, and then re-imported the details from a separate package, then imported the terrain from the original package. Not sure why this worked, but it worked.