Steps to reproduce:
1. Download 1115371_repro.zip project
2. Switch platform to UWP
3. Build "SampleScene" scene
4. Open Visual Studios solution and build project (Debug, x64, Local machine)
5. App automatically enables and disables XRSettings every 10 seconds

Results: When enabling XR for second-time app crashes

Exception thrown at 0x00007FFD27715299 (KernelBase.dll) in New Unity Project (2).exe: WinRT originate error - 0x8000000E : 'An attempt was made to acquire a buffer before it became available. Present() must be called before attempting to acquire this buffer.'.

Reproduced with: 2019.2.0a1, 2019.1.0a13, 2018.3.2f1, 2017.4.18f1
Not reproducible with OpenVR SDK on Stanalone platform

Call Stack:
> UnityPlayer.dll!VREyeTextureManager::ResolveDepthToEyeTextures(class RenderTexture ,class RenderTexture ) Unknown
UnityPlayer.dll!VRDevice::ResolveColorAndDepthToEyeTextures(class StereoRenderTexture const &,bool) Unknown
UnityPlayer.dll!CameraStackRenderingState::EndStereoRendering(void) Unknown
UnityPlayer.dll!RenderManager::RenderCameras(int,void ()(void),void ()(void)) Unknown
UnityPlayer.dll!PlayerRender(bool) Unknown
UnityPlayer.dll!`InitPlayerLoopCallbacks'::`2'::PostLateUpdateFinishFrameRenderingRegistrator::Forward() Unknown
UnityPlayer.dll!ExecutePlayerLoop(struct NativePlayerLoopSystem ) Unknown
UnityPlayer.dll!ExecutePlayerLoop(struct NativePlayerLoopSystem ) Unknown
UnityPlayer.dll!PlayerLoop(void) Unknown
UnityPlayer.dll!UnityPlayer::AppCallbacks::DoPerformUpdateAndRender(void) Unknown
UnityPlayer.dll!UnityPlayer::AppCallbacks::_AppThreadImplementation(void *) Unknown
kernel32.dll!BaseThreadInitThunk() Unknown
ntdll.dll!RtlUserThreadStart() Unknown