Getting blank screen when navigating after animation

After the animation is triggered on the first page changing pages on the menu gives a blank page.

Open App > Click any of the two buttons to trigger the animation > Menu > About Page > Blank "Error"

After that you can click the square button of the android and re-open the app will open the page normally .

Tested with Android Oreo 8.1 API 27 (Emulator and Mobile)

I'm using MasterDetail
Xamarin Forms 4.0.0.425677
NETStandard.Library 2.0.3

Project/Code
=> github/farukaf/XamarinTeste