Is it not possible for System.Object and System.Int64 to be serialized via ScriptableObject? I expected both of these types to work. However, they both are default values when I instantiate the asset. If I temporarily change both types to Int32 in my code, everything works as expected.
This kind of question comes up all the time. The list of serializable types that Unity supports are in this answer:
Sorry to revive an old thread, but have you found a way to serialize System.Object via ScriptableObject?