(Case 951296) Wrong nested canvas size when added dynamically as a child of another Canvas

Hi guys,

We've been experimenting an issue with Unity 2017.2 beta 11 (we've reported it as Case 951296):

When creating a new Canvas and setting it as child of another Canvas, it doesn't fit as supposed. I've attached an example project for you to test it.

First try the example in 2017.1.0f3 and run it so you can see how it should behave: there should be a Canvas with another canvas as a child created on runtime and a panel inside that fits the entire screen.
Then close Unity and open same project with 2017.2.0b11 and run the example: you'll see that the child canvas ignores the anchoring set from script.

Do you know if this is how it should behave? Is there any workaround for this issue?

Thanks!