RenderTargetBitmap.Render does not render DropShadowEffect on controls

[Jaex]

Describe the bug

When rendering a control to a RenderTargetBitmap using the Render method, any DropShadowEffect applied to child controls is not included in the resulting image. The effect is visible on screen but missing from the saved bitmap:

To Reproduce

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="600"
        x:Class="AvaloniaDropShadowEffectTest.MainWindow"
        Title="AvaloniaDropShadowEffectTest"
        Background="Black"
        Loaded="Window_Loaded">
    <Grid Width="300" Height="300">
        <Canvas Name="canvas" Background="White">
            <Rectangle Fill="Red" Height="200" Width="200" Margin="50">
                <Rectangle.Effect>
                    <DropShadowEffect Color="Black" BlurRadius="30"/>
                </Rectangle.Effect>
            </Rectangle>
        </Canvas>
    </Grid>
</Window>

using Avalonia;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Media.Imaging;

namespace AvaloniaDropShadowEffectTest
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object? sender, RoutedEventArgs e)
        {
            PixelSize pixelSize = new PixelSize((int)canvas.Bounds.Width, (int)canvas.Bounds.Height);
            using (RenderTargetBitmap renderBitmap = new RenderTargetBitmap(pixelSize))
            {
                renderBitmap.Render(canvas);
                renderBitmap.Save("canvas.png");
            }
        }
    }
}

Avalonia version

11.3.12
12.0.0-preview1

OS

Windows