Editor crashes when asset is imported in as a skeletal mesh, brought into a level, vertex painted using the paint tab under modes, all assets are saved, project is reopened, then level is reopened.
Crash occurs when mesh is opened as well
Does not occur in 4.18.3. Vertex color data is also not lost. Map and mesh can be opened without crash
Results: Editor crashes
Expected: Editor does not crash
Assertion failed: SerializedElementSize == 0 || SerializedElementSize == ElementSize [File:D:\Build\++UE4+Release-4.19+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 1168] Unexpected array element size. Expected 4, Got: 131073. Package can be corrupt or the array template type changed. 0x00000000DBEF3C58 KERNELBASE.dll!UnknownFunction [] 0x00000000C05F7884 UE4Editor-ApplicationCore.dll!FWindowsErrorOutputDevice::Serialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowserroroutputdevice.cpp:65] 0x00000000B5A46D8B UE4Editor-Core.dll!FOutputDevice::LogfImpl() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:70] 0x00000000B5981929 UE4Editor-Core.dll!FDebug::AssertFailed() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:419] 0x00000000A4BD33F0 UE4Editor-Engine.dll!TArray<unsigned int,TAlignedHeapAllocator<0> >::BulkSerialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\containers\array.h:1173] 0x00000000A4C15536 UE4Editor-Engine.dll!FMultiSizeIndexContainer::Serialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\engine\private\rendering\multisizeindexcontainer.cpp:163] 0x00000000A4D2D514 UE4Editor-Engine.dll!FSkeletalMeshLODRenderData::Serialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\engine\private\skeletalmeshlodrenderdata.cpp:636] 0x00000000A4E00A9B UE4Editor-Engine.dll!TIndirectArray<FSkeletalMeshLODRenderData,FDefaultAllocator>::Serialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\containers\indirectarray.h:200] 0x00000000A4E01144 UE4Editor-Engine.dll!FSkeletalMeshRenderData::Serialize() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\engine\private\skeletalmeshrenderdata.cpp:137] 0x00000000A4DBF249 UE4Editor-Engine.dll!FSkeletalMeshRenderData::Cache() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\engine\private\skeletalmeshrenderdata.cpp:83] 0x00000000A4D2254D UE4Editor-Engine.dll!USkeletalMesh::PostLoad() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\engine\private\skeletalmesh.cpp:1496] 0x00000000B46F023D UE4Editor-CoreUObject.dll!UObject::ConditionalPostLoad() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\obj.cpp:994] 0x00000000B47BAF9C UE4Editor-CoreUObject.dll!EndLoad() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1595] 0x00000000B47D311B UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1339] 0x00000000B47D2534 UE4Editor-CoreUObject.dll!LoadPackage() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1436] 0x00000000B47E9A43 UE4Editor-CoreUObject.dll!ResolveName() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:792] 0x00000000B47F43DF UE4Editor-CoreUObject.dll!StaticLoadObjectInternal() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:880] 0x00000000B47F3B03 UE4Editor-CoreUObject.dll!StaticLoadObject() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:947] 0x00000000953E3FB7 UE4Editor-ContentBrowser.dll!FAssetData::GetAsset() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\assetregistry\public\assetdata.h:284] 0x0000000095515C6F UE4Editor-ContentBrowser.dll!SContentBrowser::OnAssetsActivated() [d:\build\++ue4+release-4.19+compile\sync\engine\source\editor\contentbrowser\private\scontentbrowser.cpp:2052] 0x00000000954D8047 UE4Editor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,TTypeWrapper<void> __cdecl(TArray<FAssetData,FDefaultAllocator> const & __ptr64,enum EAssetTypeActivationMethod::Type)>::Execute() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:269] 0x00000000954E00E7 UE4Editor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SContentBrowser,0,void __cdecl(TArray<FAssetData,FDefaultAllocator> const & __ptr64,enum EAssetTypeActivationMethod::Type)>::ExecuteIfSafe() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:345] 0x0000000095520881 UE4Editor-ContentBrowser.dll!SAssetView::OnListMouseButtonDoubleClick() [d:\build\++ue4+release-4.19+compile\sync\engine\source\editor\contentbrowser\private\sassetview.cpp:3941] 0x00000000954D64F1 UE4Editor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SAssetView,0,TTypeWrapper<void> __cdecl(TSharedPtr<FAssetViewItem,0>)>::Execute() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:269] 0x00000000954DEE4F UE4Editor-ContentBrowser.dll!TBaseSPMethodDelegateInstance<0,SAssetView,0,void __cdecl(TSharedPtr<FAssetViewItem,0>)>::ExecuteIfSafe() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:345] 0x00000000954DCAB8 UE4Editor-ContentBrowser.dll!TBaseDelegate<void,TSharedPtr<FAssetViewItem,0> >::ExecuteIfBound() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:624] 0x000000009552D760 UE4Editor-ContentBrowser.dll!SListView<TSharedPtr<FAssetViewItem,0> >::Private_OnItemDoubleClicked() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\public\widgets\views\slistview.h:809] 0x0000000095520AEA UE4Editor-ContentBrowser.dll!STableRow<TSharedPtr<FAssetViewItem,0> >::OnMouseButtonDoubleClick() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\public\widgets\views\stablerow.h:288] 0x00000000AF8B64EE UE4Editor-Slate.dll!<lambda_eeb33fd1b480e3cad58a1531d90d2e14>::operator()() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5872] 0x00000000AF8879DE UE4Editor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FPointerEvent,<lambda_eeb33fd1b480e3cad58a1531d90d2e14> >() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:266] 0x00000000AF91D8A4 UE4Editor-Slate.dll!FSlateApplication::RoutePointerDoubleClickEvent() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5870] 0x00000000AF907066 UE4Editor-Slate.dll!FSlateApplication::ProcessMouseButtonDoubleClickEvent() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5857] 0x00000000AF8FA993 UE4Editor-Slate.dll!FSlateApplication::OnMouseDoubleClick() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5833] 0x00000000C05EE649 UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1730] 0x00000000C05E1B78 UE4Editor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2172] 0x00000000C05F052C UE4Editor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:889] 0x00000000C05DD679 UE4Editor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:726] 0x00000000DC871C24 USER32.dll!UnknownFunction [] 0x00000000DC87156C USER32.dll!UnknownFunction [] 0x00000000C05F1666 UE4Editor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:129] 0x00000000AC735475 UE4Editor.exe!FEngineLoop::Tick() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3263] 0x00000000AC746BD0 UE4Editor.exe!GuardedMain() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\launch\private\launch.cpp:166] 0x00000000AC746C4A UE4Editor.exe!GuardedMainWrapper() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134] 0x00000000AC754149 UE4Editor.exe!WinMain() [d:\build\++ue4+release-4.19+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210] 0x00000000AC755B57 UE4Editor.exe!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253] 0x00000000DC7B8364 KERNEL32.DLL!UnknownFunction [] 0x00000000DEC27091 ntdll.dll!UnknownFunction [] 0x00000000DEC27091 ntdll.dll!UnknownFunction []
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-57891 in the post.