When welding collision between Third Person UE4 Mannequin's left foot ball, to left foot in physics tab results in an Engine crash.

When using a Third Person UE4 Mannequin, Opening the Physics asset tab, and welding the collision between left foot ball, to left foot results in an Engine crash.

Additional Note: Using the same welding method on the right foot, and right ball works successfully without a crash.

1. Create a Third Person Template Project

2. Open up The Third Person Character Animation Blueprint -> Select Physics Asset Tab

3. In the Skeleton Tree, Navigate to "ball_L", ctrl click to select.

4. In the Skeleton Tree, Navigate to "foot_L", ctrl click to select.

5. Right click foot_l-> Collision->Weld

Result: Crash (See Call Stack)

Expected: No Crash, bodies would weld together.

Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 611]

UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [d:\ue4 monteue4main\engine\source\runtime\core\private\misc\assertionmacros.cpp:418]
UE4Editor_PhysicsAssetEditor!DispatchCheckVerify<void,<lambda_3ba7ff29edc888c97644fd71b2fde09a> >() [d:\ue4 monteue4main\engine\source\runtime\core\public\misc\assertionmacros.h:162]
UE4Editor_PhysicsAssetEditor!FPhysicsAssetEditor::HandleViewportSelectionChanged() [d:\ue4 monteue4main\engine\source\editor\physicsasseteditor\private\physicsasseteditor.cpp:220]
UE4Editor_PhysicsAssetEditor!TBaseRawMethodDelegateInstance<0,FPhysicsAssetEditor,void __cdecl(TArray<FPhysicsAssetEditorSharedData::FSelection,FDefaultAllocator> const &,TArray<FPhysicsAssetEditorSharedData::FSelection,FDefaultAllocator> const &)>::ExecuteI() [d:\ue4 monteue4main\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:518]
UE4Editor_PhysicsAssetEditor!TBaseMulticastDelegate<void,TArray<FPhysicsAssetEditorSharedData::FSelection,FDefaultAllocator> const &,TArray<FPhysicsAssetEditorSharedData::FSelection,FDefaultAllocator> const &>::Broadcast() [d:\ue4 monteue4main\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:977]
UE4Editor_PhysicsAssetEditor!FPhysicsAssetEditorSharedData::WeldSelectedBodies() [d:\ue4 monteue4main\engine\source\editor\physicsasseteditor\private\physicsasseteditorshareddata.cpp:950]
UE4Editor_PhysicsAssetEditor!TBaseSPMethodDelegateInstance<0,FPhysicsAssetEditor,0,void __cdecl(void)>::ExecuteIfSafe() [d:\ue4 monteue4main\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:355]
UE4Editor_Slate!FUICommandList::ExecuteAction() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:99]
UE4Editor_Slate!SMenuEntryBlock::OnClicked() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:1028]
UE4Editor_Slate!SMenuEntryBlock::OnMenuItemButtonClicked() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:988]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,0,FReply __cdecl(void)>::Execute() [d:\ue4 monteue4main\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:279]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\ue4 monteue4main\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:293]
UE4Editor_Slate!SMenuEntryButton::OnMouseButtonUp() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:385]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_6c1f6b862bcfb82ea6dcab28fbcc9463> >() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:271]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5589]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6193]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\ue4 monteue4main\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6166]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [d:\ue4 monteue4main\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1842]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [d:\ue4 monteue4main\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2292]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [d:\ue4 monteue4main\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1522]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [d:\ue4 monteue4main\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:772]
user32
user32
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [d:\ue4 monteue4main\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:130]
UE4Editor_Win64_DebugGame!FEngineLoop::Tick() [d:\ue4 monteue4main\engine\source\runtime\launch\private\launchengineloop.cpp:3862]
UE4Editor_Win64_DebugGame!GuardedMain() [d:\ue4 monteue4main\engine\source\runtime\launch\private\launch.cpp:168]
UE4Editor_Win64_DebugGame!GuardedMainWrapper() [d:\ue4 monteue4main\engine\source\runtime\launch\private\windows\launchwindows.cpp:145]
UE4Editor_Win64_DebugGame!WinMain() [d:\ue4 monteue4main\engine\source\runtime\launch\private\windows\launchwindows.cpp:275]
UE4Editor_Win64_DebugGame!__scrt_common_main_seh() [d:\agent\_work\2\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll