I'm building a podcast player using Maui targeting Android using the Maui and Mvvm community tookits.

I've got a page with a CollectionView defined like this:

<CollectionView
    x:Name="PodcastsListView"
    ItemsSource="{Binding Podcasts}"
    SelectionMode="Single"
    SelectionChangedCommand="{Binding SelectPodcastCommand}"
    SelectionChangedCommandParameter="{Binding SelectedItem, Source={RelativeSource Self}}">
    <CollectionView.ItemTemplate>
        <DataTemplate x:DataType="vm:PodcastViewModel">
            <HorizontalStackLayout Padding="10">
                <Image 
                    Source="{Binding ImageSource}"
                    HeightRequest="50"
                    WidthRequest="50"
                    Aspect="AspectFill" />
                <VerticalStackLayout>
                    <Label
                        Text="{Binding Podcast.Title}"
                        VerticalOptions="Center"
                        Margin="10,0,0,0" />
                    <Label
                        Text="{Binding Podcast.Description}"
                        VerticalOptions="Center"
                        Margin="10,0,0,0" />
                </VerticalStackLayout>
            </HorizontalStackLayout>
        </DataTemplate>
    </CollectionView.ItemTemplate>
</CollectionView>

The relevant parts of the view model are:

public partial class PodcastsViewModel : ObservableObject
{
    public PodcastsViewModel(IRepository<Podcast> repository, IPodcastRetriever podcastRetriever)
    {
        Podcasts = [.. repository.GetAll().Select(p => new PodcastViewModel(p))];
    }

    public ObservableCollection<PodcastViewModel> Podcasts { get; }

    [RelayCommand]
    private async Task LoadPodcastAsync()
    {
        // code to load a feed from a URL input and add it 
        // to the Podcasts collection. This bit works.
    }

    [RelayCommand]
    private async Task SelectPodcastAsync(PodcastViewModel podcast)
    {
        if (podcast is not null)
        {
            await PodcastPage.GoToAsync(podcast.Podcast.Id);
        }
    }
}

When I run the app in the Android 14 emulator from Visual Studio, I can load a feed from a URL. It gets added to the collection and appears correctly on the page. I can tap the item in the list and the PodcastsViewModel.SelectPodcastAsync method gets called, but the podcast parameter is null.

How do I fix the binding so the selected item is passed to the method? This actually worked before I update my project to .Net 9.0.