Crash launching project with Compat.MAX_GPUSKIN_BONES=75 and Preview Rendering set to Shader Model 5

Crash occurs when the user launches a project with a +75 bone skeletal mesh actor in their scene with the Compat.MAX_GPUSKIN_BONES=75 config change, and the default preview render is Shader Model 5.

This also occurs if the project launches into High End Mobile Rendering, and then the user changes it to Shader Model 5.

Likely related to [Link Removed]

1. Download or sync up the Matinee project.
2. In the DefaultEngine.ini, add the following to the [SystemSettings] section:
   • Compat.MAX_GPUSKIN_BONES=75
3. Save and close the configs.
4. Launch the project in editor.

RESULT

Crash

Fatal error: [Link Removed] [Line: 826]
Rendering thread exception:
Assertion failed: NumBones <= MaxGPUSkinBones [Link Removed] [Line: 242]

KERNELBASE.dll!UnknownFunction []
UE4Editor-Core.dll!FWindowsErrorOutputDevice::Serialize() [d:\build\++ue4\sync\engine\source\runtime\core\private\windows\windowserroroutputdevice.cpp:63]
UE4Editor-Core.dll!FOutputDevice::LogfImpl() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:70]
UE4Editor-Core.dll!FDebug::AssertFailed() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:422]
UE4Editor-Engine.dll!FGPUBaseSkinVertexFactory::FShaderDataType::UpdateBoneData() [d:\build\++ue4\sync\engine\source\runtime\engine\private\gpuskinvertexfactory.cpp:243]
UE4Editor-Engine.dll!FSkeletalMeshObjectGPUSkin::ProcessUpdatedDynamicData() [d:\build\++ue4\sync\engine\source\runtime\engine\private\skeletalrendergpuskin.cpp:459]
UE4Editor-Engine.dll!FSkeletalMeshObjectGPUSkin::UpdateDynamicData_RenderThread() [d:\build\++ue4\sync\engine\source\runtime\engine\private\skeletalrendergpuskin.cpp:312]
UE4Editor-Engine.dll!<lambda_329b6a51d194e26c00f4cb59ce3bbf32>::operator()() [d:\build\++ue4\sync\engine\source\runtime\engine\private\skeletalrendergpuskin.cpp:274]
UE4Editor-Engine.dll!TGraphTask<TEnqueueUniqueRenderCommandType<`FSkeletalMeshObjectGPUSkin::Update'::`2'::SkelMeshObjectUpdateDataCommandName,<lambda_329b6a51d194e26c00f4cb59ce3bbf32> > >::ExecuteTask() [d:\build\++ue4\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:829]
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:679]
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:575]
UE4Editor-RenderCore.dll!RenderingThreadMain() [d:\build\++ue4\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:333]
UE4Editor-RenderCore.dll!FRenderingThread::Run() [d:\build\++ue4\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:467]
UE4Editor-Core.dll!FRunnableThreadWin::Run() [d:\build\++ue4\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:76]
UE4Editor-Core.dll!FRunnableThreadWin::GuardedRun() [d:\build\++ue4\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:33]
KERNEL32.DLL!UnknownFunction []
ntdll.dll!UnknownFunction []