What Happened
I ran the Menu in AR Simulation. From there I chose the Check Support scene, then clicked Return to go back to the menu. This gave two Null Ref errors due to the camera being destroyed.

To See the Bug
Open the ARF Samples project in the Editor.
Open the Assets/Scenes/ARFoundationMenu/Menu scene.
In Build settings, select desktop platforms.
Enable XR Simulation in Project settings.
In Scene view, use the AR Simulation overlay to select the biggest office simulation environment.
Enter Play mode.
Click in Game view, scroll down until you see the Check Support button.
In Game view, click the Check Support button.
In Game view, click the Return button.
Note the errors below in Console; this is the bug.

Configuration
2021.3.0f1.2 (2021.3/staging 6eacc8284459)
MacOS 12.0.1, MacBook Pro (15-inch, 2019), 2.4 GHz 8-Core Intel Core i9
AR Foundation 5.0.0-pre.10 (f6569c5)

Errors
MissingReferenceException: The object of type 'Camera' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEngine.XR.Simulation.SimulationSessionSubsystem+SimulationProvider.Stop () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/Simulation/Subsystems/SimulationSessionSubsystem.cs:71)
UnityEngine.SubsystemsImplementation.SubsystemWithProvider`3[TSubsystem,TSubsystemDescriptor,TProvider].OnStop () (at /Users/bokken/buildslave/unity/build/Modules/Subsystems/SubsystemWithProvider.cs:56)
UnityEngine.SubsystemsImplementation.SubsystemWithProvider.Stop () (at /Users/bokken/buildslave/unity/build/Modules/Subsystems/SubsystemWithProvider.cs:22)
UnityEngine.XR.ARFoundation.SubsystemLifecycleManager`3[TSubsystem,TSubsystemDescriptor,TProvider].OnDisable () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/ARFoundation/SubsystemLifecycleManager.cs:90)
UnityEngine.XR.ARFoundation.ARSession.OnDisable () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/ARFoundation/ARSession.cs:454)

MissingReferenceException: The object of type 'Camera' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEngine.XR.Simulation.SimulationSessionSubsystem+SimulationProvider.Stop () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/Simulation/Subsystems/SimulationSessionSubsystem.cs:71)
UnityEngine.SubsystemsImplementation.SubsystemWithProvider`3[TSubsystem,TSubsystemDescriptor,TProvider].OnStop () (at /Users/bokken/buildslave/unity/build/Modules/Subsystems/SubsystemWithProvider.cs:56)
UnityEngine.SubsystemsImplementation.SubsystemWithProvider.Stop () (at /Users/bokken/buildslave/unity/build/Modules/Subsystems/SubsystemWithProvider.cs:22)
UnityEngine.SubsystemsImplementation.SubsystemWithProvider.Destroy () (at /Users/bokken/buildslave/unity/build/Modules/Subsystems/SubsystemWithProvider.cs:31)
UnityEngine.XR.Management.XRLoaderHelper.DestroySubsystem[T] () (at Library/PackageCache/com.unity.xr.management@4.2.0/Runtime/XRLoaderHelper.cs:85)
UnityEngine.XR.Simulation.SimulationLoader.Deinitialize () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/Simulation/SimulationLoader.cs:56)
UnityEngine.XR.ARFoundation.LoaderUtility.Deinitialize () (at Library/PackageCache/com.unity.xr.arfoundation@5.0.0-pre.10/Runtime/ARFoundation/LoaderUtility.cs:50)
UnityEngine.XR.ARFoundation.Samples.SceneUtility.OnSceneUnloaded (UnityEngine.SceneManagement.Scene current) (at Assets/Scripts/SceneUtility.cs:20)
UnityEngine.SceneManagement.SceneManager.Internal_SceneUnloaded (UnityEngine.SceneManagement.Scene scene) (at /Users/bokken/buildslave/unity/build/Runtime/Export/SceneManager/SceneManager.cs:253)