Question Monobehavior on Prefab Loses it's Original Values When instantiated

Hey guys so I have a game object which has a class that stores a struct that contains several List<Matrix4x4[]>.

In edit mode I can initialize the values through code.

As soon as I make it a prefab and instantiate it by dragging it into the scene from the assets folder, the values of the arrays on the monobehavior are null.

My code setup looks like this:

Code (CSharp):

1. public class Tile {
2.     public struct TileDetails{
3.         public List<Matrix4x4[]> grassMatrices;
4.         public List<Matrix4x4[]> rocksMatrices;
5.     }
6.  
7. }

Can anyone help me figure out why grassMatrices and rocksMatrices suddenly become null? I need to save this data on the prefab.

Thanks,
Aaron