Crash after Compiling Shaders for Imported SpeedTree Assets with Default Settings

A crash occurs when importing any SpeedTree asset with the default import settings.

The user reporting the issue says "the crash occurs if I have import WIND AND SMOOTH LOD checked like the default import setting for SpeedTree. If I uncheck EITHER one, the tree will import and function, but not both."

He does seem to have a workaround, but it is not optimal in case he wants to use both features on the imported SpeedTree.

Notes
This crash also occurs in the 4.11.2 release.

This crash does not occur on Windows so it appears to be platform specific.

Link to Crash Logs
[Link Removed]

1. Create new empty project.
2. Import sample SpeedTree asset (attached).
3. Keep settings at default and click 'Import'
4. Wait for shaders to finish compiling.
5. Fly the camera around the viewport.

Outcome Editor crashes a short time after compiling shaders

Expected No crash occurs.

AppleIntelHD5000GraphicsMTLDriver!ShaderBindingStage::updateConstantTable()
AppleIntelHD5000GraphicsMTLDriver!ShaderBindingStage::updateBindingTableData()
AppleIntelHD5000GraphicsMTLDriver!ShaderBindingStage::writeIf()
AppleIntelHD5000GraphicsMTLDriver!IGAccelRenderCommandEncoder::programPipeline()
AppleIntelHD5000GraphicsMTLDriver!IGAccelRenderCommandEncoder::drawIndexedPrimitives()
AppleIntelHD5000GraphicsMTLDriver!<Unknown>
UE4Editor-MetalRHI.dylib!FMetalRHICommandContext::RHIDrawIndexedPrimitive()
UE4Editor-Renderer.dylib!FMeshDrawingPolicy::DrawMesh()
UE4Editor-Renderer.dylib!void FDrawBasePassDynamicMeshAction::Process<FUniformLightMapPolicy>()
UE4Editor-Renderer.dylib!void ProcessBasePassMesh<FDrawBasePassDynamicMeshAction>()
UE4Editor-Renderer.dylib!FBasePassOpaqueDrawingPolicyFactory::DrawDynamicMesh()
UE4Editor-Renderer.dylib!FDeferredShadingSceneRenderer::RenderBasePassDynamicData()
UE4Editor-Renderer.dylib!FDeferredShadingSceneRenderer::RenderBasePass()
UE4Editor-Renderer.dylib!FDeferredShadingSceneRenderer::Render()
UE4Editor-Renderer.dylib!FRendererModule::BeginRenderingViewFamily(FCanvas*, FSceneViewFamily*)::EURCMacro_FDrawSceneCommand::DoTask()
UE4Editor-Renderer.dylib!TGraphTask<FRendererModule::BeginRenderingViewFamily(FCanvas*, FSceneViewFamily*)::EURCMacro_FDrawSceneCommand>::ExecuteTask()
UE4Editor-Core.dylib!FNamedTaskThread::ProcessTasksNamedThread()
UE4Editor-Core.dylib!FNamedTaskThread::ProcessTasksUntilQuit()
UE4Editor-Core.dylib!FTaskGraphImplementation::ProcessThreadUntilRequestReturn()
UE4Editor-RenderCore.dylib!RenderingThreadMain()
UE4Editor-RenderCore.dylib!FRenderingThread::Run()
UE4Editor-Core.dylib!FRunnableThreadPThread::Run()
UE4Editor-Core.dylib!FRunnableThreadPThread::_ThreadProc()
libsystem_pthread.dylib!<Unknown>
libsystem_pthread.dylib!<Unknown>
libsystem_pthread.dylib!<Unknown>