To reproduce:
1. Open attached Unity project "TestDungeon.zip"
2. Open "Mainscene" scene
3. Go into Play Mode

Result: Unity crashes at this point

Reproduced on: 5.6.3f1, 2017.1.0p3, 2017.2.0b7, 2017.3.0a4

========== OUTPUTING STACK TRACE ==================

0x00000000300FF374 (Mono JIT Code) [C:\buildslave\unity\build\Runtime\Export\Director\PlayableAsset.cs:54] UnityEngine.Playables.PlayableAsset:Internal_CreatePlayable (UnityEngine.Playables.PlayableAsset,UnityEngine.Playables.PlayableGraph,UnityEngine.GameObject,intptr)
0x00000000300FF45D (Mono JIT Code) (wrapper runtime-invoke) <Module>:runtime_invoke_void_object_PlayableGraph_object_intptr (object,intptr,intptr,intptr)
0x00007FFD55E95FEF (mono) [c:\buildslave\mono\build\mono\mini\mini.c:4937] mono_jit_runtime_invoke
0x00007FFD55DE8841 (mono) [c:\buildslave\mono\build\mono\metadata\object.c:2623] mono_runtime_invoke
0x0000000140919ACC (Unity) scripting_method_invoke
0x000000014090E363 (Unity) ScriptingInvocation::Invoke
0x0000000140391B60 (Unity) PlayableAssetUtility::CreatePlayable
0x00000001417D9303 (Unity) PlayableDirector::CreatePlayableAssetInstance
0x00000001417DA4D2 (Unity) PlayableDirector::Instantiate
0x00000001417DB33D (Unity) PlayableDirector::AddToManager
0x0000000140983731 (Unity) AwakeFromLoadQueue::InvokePersistentManagerAwake
0x0000000140986619 (Unity) AwakeFromLoadQueue::PersistentManagerAwakeFromLoad
0x00000001406B2C87 (Unity) LoadSceneOperation::CompleteAwakeSequence
0x00000001406B313A (Unity) LoadSceneOperation::CompletePreloadManagerLoadSceneEditor
0x00000001406B82B3 (Unity) LoadSceneOperation::IntegrateMainThread
0x00000001406B6F68 (Unity) PreloadManager::UpdatePreloadingSingleStep
0x00000001406B7108 (Unity) PreloadManager::WaitForAllAsyncOperationsToComplete
0x0000000140B7BAF2 (Unity) EditorSceneManager::RestoreSceneBackups
0x00000001410B70BF (Unity) PlayerLoopController::EnterPlayMode
0x00000001410B7999 (Unity) PlayerLoopController::SetIsPlaying
0x00000001410B87E5 (Unity) Application::TickTimer
0x00000001412C0DCD (Unity) MainMessageLoop
0x00000001412C2704 (Unity) WinMain
0x0000000141DD5748 (Unity) __tmainCRTStartup
0x00007FFD955E2774 (KERNEL32) BaseThreadInitThunk
0x00007FFD97F30D51 (ntdll) RtlUserThreadStart

========== END OF STACKTRACE ===========