Problem with "Your First ASP.NET 5 Web App Using Visual Studio"

I am a retired IT dinosaur who wants to learn this new technology. I started by watching the excellent Pluralsight courses on MVC 4 and MVC 5, and then built the tutorial exercise in the title of this post from the page docs.asp.net.

When I run it on my PC, I see the list of books as demonstrated in the tutorial. In order to see how the application works, I edited a book. When I click the "Save" button, the application crashes. It appears to be executing two methods: .SaveChanges() and .Update() in the controller to update a row , but the primary key is not set.

My education will undoubtedly teach me what's wrong. My question is: Shouldn't the generated application do these simple things "out of the box"?

EDIT: I have been advised to make it easier to look at this problem by providing more detail:

1. Go to https://docs.asp.net/en/latest/
2. Click Tutorials in LHS menu
3. Click topmost dot point (link) Your First ASP.NET 5 Web App Using Visual Studio
4. Follow instructions as far as displaying a list of books (this took me about 10-15 minutes)
5. Click "Edit" on any book and attempt to make a change and save. Application crashes.

Hope this helps.