Rare crash occurs in CoreAudio in Vehicle Game on Mac when quitting.

This is a very rare crash that I encountered in Vehicle Game and so far have not been able to reproduce, however checking the crash history it has been seen before in the wild.

This issue may be related to UE-40953 as the crash occurred when I quit the game with that issue happening. I have tried to get this crash again with the above issue, but as I said it is rare.

Setup:
Have access to Vehicle Game

Repro:

1. Launch Vehicle Game
2. Press Escape to open the menu
3. Restart the track
4. Press Escape twice to open and close the menu
5. Press the Escape key again to pause the game and open the menu
6. Click on Quit

Repro Rate:
1/5

VehicleGame!FCoreAudioSoundSource::FreeResources()
VehicleGame!FCoreAudioSoundSource::~FCoreAudioSoundSource()
VehicleGame!FAudioDevice::Teardown()
VehicleGame!FAudioDeviceManager::ShutdownAudioDevice()
VehicleGame!FAudioDeviceManager::ShutdownAllAudioDevices()
VehicleGame!UEngine::ShutdownAudioDeviceManager()
VehicleGame!FEngineLoop::Exit()
VehicleGame!GuardedMain()
VehicleGame!<Unknown>
VehicleGame!<Unknown>
Foundation!Unknown()
libsystem_pthread.dylib!<Unknown>
libsystem_pthread.dylib!<Unknown>
libsystem_pthread.dylib!<Unknown>