WebView not working inside MasterDetailPage Page and IsVisible causing crashes.

Hello.

I followed this guide here to create a project that uses MasterDetailPage
https://www.syntaxismyui.com/xamarin-forms-masterdetail-page-navigation-recipe/

But my issue is now that WebViews aren't visible inside of the content pages, they are just blank. I've tried a lot of different WebView samples.
Meanwhile calling on IsVisible, either directly in XAML or the code-behind causes the MasterDetailPage to crash.

Should I consider using a different MasterDetailPage sample or is this an issue with MasterDetailPage in general?