Xamarin.Forms Binding Specified cast is not valid

I have a weird exception where the Compiler tells me that the Specified cast is not valid even though what im doing is very Simple.

I have a ListView binded to a ObservableCollection. And inside my Listview is a ViewCell with a Grid. Xamarin.Forms Version 2.3.2.127

<ListView ItemsSource="{Binding GiftCollection}">
      <ListView.ItemTemplate>
        <DataTemplate>
          <ViewCell>
            <ViewCell.View>
              <Grid>
          <Grid.RowDefinitions>
            <RowDefinition Height="20"/>
            <RowDefinition Height="20"/>
          </Grid.RowDefinitions>
          <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="40"/>
          </Grid.ColumnDefinitions>

          <Label Grid.Row="0" Grid.Column="0" Text="{Binding GiftName}"/>
          <Label Grid.Row="1" Grid.Column="0" Text="{Binding GiftDescription}"/>
          <Image Grid.Row="0" Grid.RowSpan="2" Grid.Column="1" Source="{Binding GiftImage}"/>
        </Grid>
        </ViewCell.View>
      </ViewCell>
        </DataTemplate>
      </ListView.ItemTemplate>
    </ListView>

Model:

public class GiftModel {

        public string GiftName { get; set; }
        public string GiftDescription { get; set; }
        public ImageSource GiftImage { get; set; }
    }

ViewModel:

public class NextRoundViewModel : BaseViewModel {

        public NextRoundViewModel(ApplicationModel applicationModel) {
            ApplicationModel = applicationModel;
            Initialize();
        }

        public ApplicationModel ApplicationModel { get; set; }
        public ObservableCollection<GiftModel> GiftCollection { get; set; }
        public string CurrentRound => "Runde 2";

        private void Initialize() {
            GiftCollection = new ObservableCollection<GiftModel> {
                new GiftModel {
                    GiftName = "100 Punkte",
                    GiftDescription = "Test",
                    GiftImage = ImageSource.FromFile("Star.png"),
                },
                new GiftModel {
                    GiftName = "200 Punkte",
                    GiftDescription = "Test",
                    GiftImage = ImageSource.FromFile("Star.png"),
                },
                new GiftModel {
                    GiftName = "300 Punkte",
                    GiftDescription = "Test",
                    GiftImage = ImageSource.FromFile("Star.png"),
                },
            };
        }
    }

So ive tried everything but if i use for example a TextCell the Exception is gone. System.InvalidCastException: Specified cast is not valid. It is just weird because i dont know where to look for the Bug.