Ensure occurs when turning on Constraints in Advanced Show Flags

LogOutputDevice:Error: === Handled ensure: ===
LogOutputDevice:Error: Ensure condition failed: false [File:D:\Build\++UE4+Release-4.15+Compile\Sync\Engine\Source\Runtime\Engine\Private\PrimitiveSceneProxy.cpp] [Line: 598]
LogOutputDevice:Error: PrimitiveComponent tried to render with Material MaterialInstanceDynamic_10, which was not present in the component's GetUsedMaterials results
LogOutputDevice:Error:     Owner: SK_Mop_4, Resource: SK_Mop
LogOutputDevice:Error: Stack: 
LogOutputDevice:Error: UE4Editor-Core.dll!FWindowsPlatformStackWalk::StackWalkAndDump() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsplatformstackwalk.cpp:200]
LogOutputDevice:Error: UE4Editor-Core.dll!FDebug::EnsureFailed() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:233]
LogOutputDevice:Error: UE4Editor-Core.dll!FDebug::OptionallyLogFormattedEnsureMessageReturningFalse() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:360]
LogOutputDevice:Error: UE4Editor-Engine.dll!FPrimitiveSceneProxy::VerifyUsedMaterial() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\primitivesceneproxy.cpp:598]
LogOutputDevice:Error: UE4Editor-Engine.dll!FMeshElementCollector::AddMesh() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\scenemanagement.cpp:233]
LogOutputDevice:Error: UE4Editor-Engine.dll!FDynamicMeshBuilder::GetMesh() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\dynamicmeshbuilder.cpp:557]
LogOutputDevice:Error: UE4Editor-Engine.dll!FDynamicMeshBuilder::GetMesh() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\dynamicmeshbuilder.cpp:483]
LogOutputDevice:Error: UE4Editor-Engine.dll!GetConeMesh() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\primitivedrawingutils.cpp:669]
LogOutputDevice:Error: UE4Editor-Engine.dll!FConstraintInstance::DrawConstraintImp() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\physicsengine\physdrawing.cpp:965]
LogOutputDevice:Error: UE4Editor-Engine.dll!UPhysicsAsset::DrawConstraints() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\physicsengine\physdrawing.cpp:779]
LogOutputDevice:Error: UE4Editor-Engine.dll!FSkeletalMeshSceneProxy::DebugDrawPhysicsAsset() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\skeletalmesh.cpp:5242]
LogOutputDevice:Error: UE4Editor-Engine.dll!FSkeletalMeshSceneProxy::GetMeshElementsConditionallySelectable() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\skeletalmesh.cpp:4936]
LogOutputDevice:Error: UE4Editor-Engine.dll!FSkeletalMeshSceneProxy::GetDynamicMeshElements() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\skeletalmesh.cpp:4865]
LogOutputDevice:Error: UE4Editor-Renderer.dll!FSceneRenderer::GatherDynamicMeshElements() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\renderer\private\scenevisibility.cpp:1958]
LogOutputDevice:Error: UE4Editor-Renderer.dll!FSceneRenderer::ComputeViewVisibility() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\renderer\private\scenevisibility.cpp:2617]
LogOutputDevice:Error: UE4Editor-Renderer.dll!FDeferredShadingSceneRenderer::InitViews() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\renderer\private\scenevisibility.cpp:2860]
LogOutputDevice:Error: UE4Editor-Renderer.dll!FDeferredShadingSceneRenderer::Render() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\renderer\private\deferredshadingrenderer.cpp:589]
LogOutputDevice:Error: UE4Editor-Renderer.dll!RenderViewFamily_RenderThread() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\renderer\private\scenerendering.cpp:1728]
LogOutputDevice:Error: UE4Editor-Renderer.dll!TGraphTask<`FRendererModule::BeginRenderingViewFamily'::`21'::EURCMacro_FDrawSceneCommand>::ExecuteTask() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:883]
LogOutputDevice:Error: UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:954]
LogOutputDevice:Error: UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:701]
LogOutputDevice:Error: UE4Editor-RenderCore.dll!RenderingThreadMain() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:325]
LogOutputDevice:Error: UE4Editor-RenderCore.dll!FRenderingThread::Run() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:459]
LogOutputDevice:Error: UE4Editor-Core.dll!FRunnableThreadWin::Run() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:76]
LogOutputDevice:Error: UE4Editor-Core.dll!FRunnableThreadWin::GuardedRun() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:33]
LogOutputDevice:Error: KERNEL32.DLL!0x000000007A988364
LogOutputDevice:Error: ntdll.dll!0x000000007AEC70D1