EF AddOrUpdate Seed does not Update Child Entities

I'm having some issues Seeding data and I was able to reproduce the issue with a very small application.
Given you have this Seed Method:

    protected override void Seed(JunkContext context)
    {
        context.Junks.AddOrUpdate(x => x.Name,
            new Junk()
            {
                Name = "BANANAS!!",
                Item = new JunkItem()
                {
                    Name = "APPLES!!!"
                }
            }
        );
    }

when you run update-database in the PMC all of the entities get created successfully. Good.
But when you wish to go and update the database, say your seed method is now this:

    protected override void Seed(JunkContext context)
    {
        context.Junks.AddOrUpdate(x => x.Name,
            new Junk()
            {
                Name = "BANANAS!!",
                Item = new JunkItem()
                {
                    Name = "ORANGES!!!"
                }
            }
        );
    }

The child entity is not updated. It seems the only way we can re-seed is to wipe the database and reseed everything. I think I understand as to why this does not work the way I expect it to, but perhaps someone could point me in the right direction to update this seed method accordingly. I know I could just write out context.JunkItems. (...) but that seems like it would beat the whole purpose of 'AddOrUpdate'.

I think I would have to define 'keys' for each child entity. Example: 'Junk' gets x => x.Name but 'JunkItem' currently has to 'update key' set. I'm assuming that's the issue, but how would I go about handling that?