[Bug] [iOS13] A portion of the page is pushed off screen when using Large titles and SearchBar

Description

When using Large titles and a SearchBar in iOS 13, the bottom part of a page (SearchBar height?) is pushed off screen when using a listview and another view in a StackLayout. This is visible when scrolling the ListView up.

Example:

Notice that the BoxView (height 100) is pushed off screen until scrolling up.

Code: App.xaml:

public App()
{
    InitializeComponent();

    var page = new Xamarin.Forms.NavigationPage(new MainPage());
    page.On<Xamarin.Forms.PlatformConfiguration.iOS>().SetPrefersLargeTitles(true);
    MainPage = page;
}

MainPage.xaml

<?xml version="1.0" encoding="utf-8"?>
<ContentPage
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:d="http://xamarin.com/schemas/2014/forms/design"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:ios="clr-namespace:Xamarin.Forms.PlatformConfiguration.iOSSpecific;assembly=Xamarin.Forms.Core"
    Title="Hello"
    NavigationPage.HasNavigationBar="True"
    ios:Page.LargeTitleDisplay="Automatic"
    mc:Ignorable="d"
    x:Class="Search.MainPage"
    x:Name="_rootPage">
    <StackLayout x:Name="_outerLayout">
        <ListView x:Name="_list" BackgroundColor="AntiqueWhite" HasUnevenRows="True" />
        <BoxView HeightRequest="100" BackgroundColor="Aqua" />
    </StackLayout>
</ContentPage>

MainPage.xaml.cs

public partial class MainPage : ContentPage
{
    public ObservableCollection<string> _data;

    public MainPage()
    {
        InitializeComponent();

        _data = new ObservableCollection<string>() { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };
        _list.ItemsSource = _data;
    }
}

MainPageRenderer.cs

[assembly: ExportRenderer(typeof(MainPage), typeof(MainPageRenderer))]
namespace Search.iOS.CustomRenderers
{
    public class MainPageRenderer : Xamarin.Forms.Platform.iOS.PageRenderer, IUISearchControllerDelegate
    {
        private UISearchController _searchController;

        public override void WillMoveToParentViewController(UIViewController parent)
        {
            base.WillMoveToParentViewController(parent);
            SetSearchController(parent);
        }

        void SetSearchController(UIViewController parent)
        {
            _searchController = new UISearchController(searchResultsController: null);

            _searchController.HidesNavigationBarDuringPresentation = false;
            _searchController.DimsBackgroundDuringPresentation = false;
            _searchController.SearchBar.SearchBarStyle = UISearchBarStyle.Minimal;
            _searchController.AutomaticallyAdjustsScrollViewInsets = false;
            _searchController.Delegate = this;

            parent.NavigationItem.HidesSearchBarWhenScrolling = false;
            parent.NavigationItem.SearchController = _searchController;
        }
    }
}

Steps to Reproduce

1. Pull and run https://github.com/GerhardSchreurs/SearchDemo in iOS
2. Observe and scroll

Expected Behavior

I should see the whole BoxView after launch

Actual Behavior

I only see a part of the BoxView after launch. When scrolling down, the whole BoxView is visible, when scrolling fully up, part of the BoxView disappears

Basic Information

• Version with issue: iOS 13
• Last known good version: iOS 12
• IDE: Visual Studio for Mac

Screenshots

This shows the expected result and actual result after launch

Reproduction Link

https://github.com/GerhardSchreurs/SearchDemo

Please note...

If this is not a bug (I'm unaware if this same problem would arise when creating a same app using Xcode only), and there are workarounds / settings / flags that circumvent the described problem, please let me know. But as stated, this does not occur in iOS 12.

====================

Addendum:

I updated the repository to showcase the following: Watch what happens when you focus the SearchBar, navigate to a details page and navigate back: