4.16 Project to 4.19 & 4.20 - MorphTargetWeights Crash

I have a project that runs fine in 4.16 and is fine when I upgraded it to 4.18 through the launcher however when I use the launcher to upgrade it to 4.19 and 4.20 it crashes (see log below) when I start to play the game. Appears to be related to morph targets

The following error is from 4.19 log :

[2018.09.12-15.33.37:668][949]LogShaderCompilers: Display: Shaders left to compile 25386
[2018.09.12-15.33.37:907][949]LogStats: FPlatformStackWalk::StackWalkAndDump - 1.011 s
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: === Handled ensure: ===
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error:
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: Ensure condition failed: DynamicData->MorphTargetWeights.Num() == LODData.MorphTargetVertexInfoBuffers.GetNumMorphs() [File:D:\Build++UE4+Release-4.19+Compile\Sync\Engine\Source\Runtime\Engine\Private\SkeletalRenderGPUSkin.cpp] [Line: 357]
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error:
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: Stack:
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FE39B706 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FE0FAE3A UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FE10ECD6 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FC4E5111 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FC4FCD46 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FC4A5FDE UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FC4BFDE4 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FDFCB713 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FDFCBD3A UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x000000004F1B3CC9 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x000000004F1B4CF6 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FE399FFC UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x00000000FE38ED63 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x0000000079E73034 KERNEL32.DLL!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error: [Callstack] 0x000000007A101431 ntdll.dll!UnknownFunction []
[2018.09.12-15.33.37:907][949]LogOutputDevice: Error:
[2018.09.12-15.33.37:907][949]LogStats: SubmitErrorReport - 0.000 s
[2018.09.12-15.33.46:468][949]LogShaderCompilers: Display: Shaders left to compile 25376
[2018.09.12-15.33.46:468][949]LogShaderCompilers: Display: Shaders left to compile 25366
[2018.09.12-15.33.46:468][949]LogShaderCompilers: Display: Shaders left to compile 25356
[2018.09.12-15.33.46:480][949]LogShaderCompilers: Display: Shaders left to compile 25346
[2018.09.12-15.33.46:599][949]LogStats: SendNewReport - 8.693 s
[2018.09.12-15.33.46:599][949]LogStats: FDebug::EnsureFailed - 9.726 s
[2018.09.12-15.33.47:080][949]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2018.09.12-15.33.47:591][949]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2018.09.12-15.33.47:695][949]LogWindows: Error: === Critical error: ===
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error: Fatal error: [File:D:\Build++UE4+Release-4.19+Compile\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 819]
[2018.09.12-15.33.47:695][949]LogWindows: Error: Rendering thread exception:
[2018.09.12-15.33.47:695][949]LogWindows: Error: Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\Build++UE4+Release-4.19+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 610]
[2018.09.12-15.33.47:695][949]LogWindows: Error: Array index out of bounds: 58 from an array of size 58
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x0000000076ACA388 KERNELBASE.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x000000004E807884 UE4Editor-ApplicationCore.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FE1B6D9B UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FE0F1949 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4B2257 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4FF2D3 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4E5158 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4FCD46 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4A5FDE UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FC4BFDE4 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FDFCB713 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FDFCBD3A UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x000000004F1B3CC9 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x000000004F1B4CF6 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FE399FFC UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x00000000FE38ED63 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x0000000079E73034 KERNEL32.DLL!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x000000007A101431 ntdll.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error: [Callstack] 0x000000007A101431 ntdll.dll!UnknownFunction []
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:695][949]LogWindows: Error:
[2018.09.12-15.33.47:705][949]LogExit: Executing StaticShutdownAfterError
[2018.09.12-15.33.47:832][949]LogWindows: FPlatformMisc::RequestExit(1)
[2018.09.12-15.33.47:861][949]Log file closed, 09/12/18 16:33:47

Log from 4.20 :

[2018.09.12-15.19.18:238][613]LogStats: FPlatformStackWalk::StackWalkAndDump - 2.477 s
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: === Handled ensure: ===
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error:
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: Ensure condition failed: DynamicData->MorphTargetWeights.Num() == LODData.MorphTargetVertexInfoBuffers.GetNumMorphs() [File:D:\Build++UE4\Sync\Engine\Source\Runtime\Engine\Private\SkeletalRenderGPUSkin.cpp] [Line: 367]
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error:
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: Stack:
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfe3a71e6 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfe0e0c82 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfe0fb346 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfc48aadc UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfc4a3772 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfc44821e UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfc468a7d UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfdf61f92 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfdf62456 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffc4a1075f9 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffc4a108574 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfe3a6b6c UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffbfe3a17b7 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffc79e73034 KERNEL32.DLL!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error: [Callstack] 0x00007ffc7a101431 ntdll.dll!UnknownFunction []
[2018.09.12-15.19.18:238][613]LogOutputDevice: Error:
[2018.09.12-15.19.18:255][613]LogStats: SubmitErrorReport - 0.016 s
[2018.09.12-15.19.27:266][613]LogStats: SendNewReport - 8.929 s
[2018.09.12-15.19.27:266][613]LogStats: FDebug::EnsureFailed - 11.424 s
[2018.09.12-15.19.27:266][613]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2018.09.12-15.19.28:437][613]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2018.09.12-15.19.28:555][613]LogWindows: Error: === Critical error: ===
[2018.09.12-15.19.28:555][613]LogWindows: Error:
[2018.09.12-15.19.28:555][613]LogWindows: Error: Fatal error: [File:D:\Build++UE4\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 826]
[2018.09.12-15.19.28:555][613]LogWindows: Error: Rendering thread exception:
[2018.09.12-15.19.28:555][613]LogWindows: Error: Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 611]
[2018.09.12-15.19.28:555][613]LogWindows: Error: Array index out of bounds: 58 from an array of size 58
[2018.09.12-15.19.28:555][613]LogWindows: Error:
[2018.09.12-15.19.28:555][613]LogWindows: Error:
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffc76aca388 KERNELBASE.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffc49ac6850 UE4Editor-ApplicationCore.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfe1462ec UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfe0d51cb UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfc457b9b UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfc4a5aed UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfc48ab23 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfc4a3772 UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:555][613]LogWindows: Error: [Callstack] 0x00007ffbfc44821e UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffbfc468a7d UE4Editor-Engine.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffbfdf61f92 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffbfdf62456 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffc4a1075f9 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffc4a108574 UE4Editor-RenderCore.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffbfe3a6b6c UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffbfe3a17b7 UE4Editor-Core.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffc79e73034 KERNEL32.DLL!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error: [Callstack] 0x00007ffc7a101431 ntdll.dll!UnknownFunction []
[2018.09.12-15.19.28:556][613]LogWindows: Error:
[2018.09.12-15.19.28:556][613]LogWindows: Error:
[2018.09.12-15.19.28:556][613]LogWindows: Error:
[2018.09.12-15.19.28:556][613]LogWindows: Error:
[2018.09.12-15.19.28:564][613]LogExit: Executing StaticShutdownAfterError
[2018.09.12-15.19.28:746][613]LogWindows: FPlatformMisc::RequestExit(1)
[2018.09.12-15.19.28:765][613]Log file closed, 09/12/18 16:19:28

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