The Media sample breaks when you interact with it

[PathogenDavid]

Environment

This repo, but with the latest Avalonia CI build (Here's the fork, it's nothing special: https://github.com/PathogenPlayground/XamlControlsGallery/commit/988dc68424bc8289c5183d404959af3f44ef4376)

Windows 10 2004

NVIDIA GTX 1080, driver version 451.67 -- Latest driver version (456.38) still exhibits the issue

Steps to reproduce

1. Launch the app
2. Go to the Media tab
3. Mess with the yaw slider (which slider doesn't matter)

Expected behavior

Teapot go spin

Actual behavior

The window will randomly flicker into a glitchy mess (either a blank transparent canvas, broken teapot, or a mess of polygons.)

I think the missing controls might just be a dirty rectangles problem, if I hover around they will reappear:

Do it enough and eventually it'll crash an AccessViolationException at MediaPage.xaml.cs:373 with the following stack trace:

 	libglesv2.dll!00007ffeb9f006a2()	Unknown
 	libglesv2.dll!00007ffeba02b019()	Unknown
 	libglesv2.dll!00007ffeb9fc02be()	Unknown
 	libglesv2.dll!00007ffeb9fc0dc9()	Unknown
 	libglesv2.dll!00007ffeb9fc39f1()	Unknown
 	libglesv2.dll!00007ffeba033ed0()	Unknown
 	libglesv2.dll!00007ffeb9ee6a70()	Unknown
 	libglesv2.dll!00007ffeb9ebcd45()	Unknown
 	[Managed to Native Transition]	
>	XamlControlsGallery.dll!XamlControlsGallery.Pages.OpenGlPageControl.OnOpenGlRender(Avalonia.OpenGL.GlInterface gl, int fb) Line 373	C#
 	Avalonia.OpenGL.dll!Avalonia.OpenGL.OpenGlControlBase.Render(Avalonia.Media.DrawingContext context)	Unknown
 	Avalonia.Visuals.dll!Avalonia.Rendering.SceneGraph.SceneBuilder.Update(Avalonia.Media.DrawingContext context, Avalonia.Rendering.SceneGraph.Scene scene, Avalonia.Rendering.SceneGraph.VisualNode node, Avalonia.Rect clip, bool forceRecurse)	Unknown
 	Avalonia.Visuals.dll!Avalonia.Rendering.SceneGraph.SceneBuilder.Update(Avalonia.Rendering.SceneGraph.Scene scene, Avalonia.VisualTree.IVisual visual)	Unknown
 	Avalonia.Visuals.dll!Avalonia.Rendering.DeferredRenderer.UpdateScene()	Unknown
 	Avalonia.Visuals.dll!Avalonia.Rendering.DeferredRenderer.UpdateSceneIfNeeded()	Unknown
 	Avalonia.Base.dll!Avalonia.Threading.JobRunner.Job.Avalonia.Threading.JobRunner.IJob.Run()	Unknown
 	Avalonia.Base.dll!Avalonia.Threading.JobRunner.RunJobs(Avalonia.Threading.DispatcherPriority? priority)	Unknown
 	Avalonia.Win32.dll!Avalonia.Win32.Win32Platform.WndProc(System.IntPtr hWnd, uint msg, System.IntPtr wParam, System.IntPtr lParam)	Unknown
 	[Native to Managed Transition]	
 	user32.dll!00007fff347be858()	Unknown
 	user32.dll!00007fff347be299()	Unknown
 	[Managed to Native Transition]	
 	Avalonia.Win32.dll!Avalonia.Win32.Win32Platform.RunLoop(System.Threading.CancellationToken cancellationToken)	Unknown
 	Avalonia.Base.dll!Avalonia.Threading.Dispatcher.MainLoop(System.Threading.CancellationToken cancellationToken)	Unknown
 	Avalonia.Controls.dll!Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(string[] args)	Unknown
 	Avalonia.Controls.dll!Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime<Avalonia.AppBuilder>(Avalonia.AppBuilder builder, string[] args, Avalonia.Controls.ShutdownMode shutdownMode)	Unknown
 	XamlControlsGallery.NetCore.dll!XamlControlsGallery.Program.Main(string[] args) Line 13	C#