How to reproduce:
1. Create a new blank app and add a new default scene.
2. Switch build platform to "Universal Windows Platform".
3. Change (Player Settings->UWP Settings->Other Settings->Scripting Backend) to ".NET" or il2cpp
4. Under (Player Settings->UWP Settings->XR Settings), turn on virtual reality support and add the "Windows Mixed Reality" SDK.
5. Build your Windows Store App project and run it without an HMD attached

Actual result: The app stuck with multiple messages spawns "Screen position out of view frustum (screen pos 0.000000, 0.000000, 1000.000000) (Camera rect 0 0 0 0)
(Filename: C:\buildslave\unity\build\Runtime/Camera/Camera.cpp Line: 3124)"

Reproduced with: 2017.3.1p2, 2018.1.0b9, 2018.2.0a1
Not reproduced with: 2017.3.1f1

Regression since: 2017.3.1p1

Note:
- Reproduces on x64 and x86
- Before 2017.3.1f1 app crashes with the error message: "Callback registration failed. Increase kMaxCallback."