RefreshView not triggering group header converter

I have a listview (SfListView version: 16.4.0.53) bound to a list of objects. The listview is grouped by one of the properties and I am using a converter to show summary information in group header. When the user clicks one of the buttons I update the datasource and call ListView.RefreshView(). The converter for the item binding is getting called but the converter of the group header isn't so the header shows out of date information.

This is how my group header template looks like:

Xaml    <syncfusion:SfListView AllowGroupExpandCollapse="True"                        ItemsSource="{Binding contactsinfo}">                  <syncfusion:SfListView.GroupHeaderTemplate>                      <DataTemplate>                          <Grid >                              <Grid.ColumnDefinitions>                                  <Image Source="{Binding IsExpand, Converter={StaticResource BoolToImageConverter}}"/>                              </StackLayout>                          </Grid>                      </DataTemplate>                  </syncfusion:SfListView.GroupHeaderTemplate>  </syncfusion:SfListView>    Converter      public class BoolToImageConverter : IValueConverter      {          public object Convert(object value, Type targetType, object parameter, CultureInfo culture)          {              if ((bool)value)              {                  return ImageSource.FromResource("SfListViewSample.Images.GroupExpand.png");              }              else              {                  return ImageSource.FromResource("SfListViewSample.Images.GroupCollapse.png");              }          }            public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)          {              throw new NotImplementedException();          }      }

I am not trying to show expand/collapse image. I just need to set image based on the Items in the group that's why I am passing Items collection to the converter.

Xaml      <syncfusion:SfListView AllowGroupExpandCollapse="True" ItemsSource="{Binding contactsinfo}">      <syncfusion:SfListView.GroupHeaderTemplate>                      <DataTemplate>                          <Grid BackgroundColor="#E4E4E4">                              <Grid.ColumnDefinitions>                                  <ColumnDefinition Width="*"/>                                  <ColumnDefinition Width="*"/>                              </Grid.ColumnDefinitions>                              <StackLayout Orientation="Horizontal" HorizontalOptions="Start" VerticalOptions="Center" Padding="10,0,0,0">                                  <Label Text="{Binding Key}" TextColor="Black" FontSize="Medium"/>                              </StackLayout>                              <StackLayout Orientation="Horizontal" Grid.Column="1" Padding="0,0,20,0"                                                HorizontalOptions="EndAndExpand" VerticalOptions="Center">                                  <Label Text="{Binding Count}" TextColor="Black" FontSize="Medium"/>                                  <Label Text="Item(s)" TextColor="Black" FontSize="Medium"/>                                  <Image Source="{Binding Items, Converter={StaticResource BoolToImageConverter}}" HeightRequest="50" WidthRequest="100"/>                              </StackLayout>                          </Grid>                      </DataTemplate>                  </syncfusion:SfListView.GroupHeaderTemplate>   </syncfusion:SfListView>      Converter      public class BoolToImageConverter : IValueConverter      {          public object Convert(object value, Type targetType, object parameter, CultureInfo culture)          {              var image = ImageSource.FromResource("SfListViewSample.Images.GroupExpand.png");              var items = value as IEnumerable;              if (items != null)              {                  var groupitems = items.ToList<object>().ToList<object>();                    if (groupitems != null)                  {                      for (int i = 0; i < groupitems.Count; i++)                      {                          var contact = groupitems[i] as Contacts;                          if (contact.ContactName == "Kenny")                              image = ImageSource.FromResource("SfListViewSample.Images.new.jpg");                      }                  }              }                return image;          }            public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)          {              throw new NotImplementedException();          }      }

That's what I am doing but when I update any item the group header image doesn't change even if I call RefreshView on the listview.