Unable to cook Animation Blueprint with ModifyBone Node

Since updating from 4.8.3 to 4.9.0 I cannot cook any Animation Blueprint that contains a ModifyBone node. Also replacing all existing nodes with new created nodes does not help. Here is the log output of ABP_Flag that contains four ModifyBone nodes:

LogProperty:Error: UStructProperty::Serialize Loading: Property 'StructProperty /Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C:AnimGraphNode_ModifyBone_7AE3FA0B49C08555655ED5A0DAA6B455'. Unknown structure.
LogProperty:Error: UStructProperty::Serialize Loading: Property 'StructProperty /Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C:AnimGraphNode_ModifyBone_574C07AE49C974EB987A2EBD2CC3829B'. Unknown structure.
LogProperty:Error: UStructProperty::Serialize Loading: Property 'StructProperty /Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C:AnimGraphNode_ModifyBone_210B167644B5CEBEF598159E4ABC7B67'. Unknown structure.
LogProperty:Error: UStructProperty::Serialize Loading: Property 'StructProperty /Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C:AnimGraphNode_ModifyBone_940E3F6242977286E638BABF8FD15E8B'. Unknown structure.
LogAnimation:Warning: Invalid animation root node index 6 on '/Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C' (only 3 nodes)
LogOutputDevice: === Handled error: ===
Ensure condition failed: bValidRootIndex [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.9\Engine\Source\Runtime\Engine\Private\Animation\AnimBlueprintGeneratedClass.cpp] [Line: 234]
Stack: 
UE4Editor-Core.dll!FWindowsPlatformStackWalk::StackWalkAndDump() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\windows\windowsplatformstackwalk.cpp:175]
UE4Editor-Core.dll!FDebug::EnsureFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\misc\outputdevice.cpp:258]
UE4Editor-Core.dll!FDebug::OptionallyLogFormattedEnsureMessageReturningFalse() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\misc\outputdevice.cpp:368]
UE4Editor-Engine.dll!UAnimBlueprintGeneratedClass::Link() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\animation\animblueprintgeneratedclass.cpp:234]
UE4Editor-CoreUObject.dll!UClass::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\class.cpp:3393]
UE4Editor-Engine.dll!UBlueprintGeneratedClass::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\blueprintgeneratedclass.cpp:757]
UE4Editor-CoreUObject.dll!FLinkerLoad::Preload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3143]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3792]
UE4Editor-CoreUObject.dll!FLinkerLoad::IndexToObject() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3982]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3505]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExportAndPreload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2661]
UE4Editor-CoreUObject.dll!FLinkerLoad::LoadAllObjects() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2769]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1032]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::Verify() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1905]
UE4Editor-CoreUObject.dll!FLinkerLoad::FinalizeCreation() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1815]
UE4Editor-CoreUObject.dll!FLinkerLoad::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:666]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateLinker() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:404]
UE4Editor-CoreUObject.dll!GetPackageLinker() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linker.cpp:570]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:936]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::Verify() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1905]
UE4Editor-CoreUObject.dll!FLinkerLoad::FinalizeCreation() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1815]
UE4Editor-CoreUObject.dll!FLinkerLoad::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:666]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateLinker() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:404]
UE4Editor-CoreUObject.dll!GetPackageLinker() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linker.cpp:570]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:936]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3926]
UE4Editor-CoreUObject.dll!FLinkerLoad::ResolveAllImports() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:1026]
UE4Editor-CoreUObject.dll!FLinkerLoad::FinalizeBlueprint() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:1090]
UE4Editor-CoreUObject.dll!FLinkerLoad::Preload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3190]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3792]
UE4Editor-CoreUObject.dll!FLinkerLoad::IndexToObject() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3982]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3505]
UE4Editor-CoreUObject.dll!FLinkerLoad::IndexToObject() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3982]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3505]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExportAndPreload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2661]
UE4Editor-CoreUObject.dll!FLinkerLoad::LoadAllObjects() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2769]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1032]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3926]
UE4Editor-CoreUObject.dll!FLinkerLoad::ResolveDependencyPlaceholder() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:915]
UE4Editor-CoreUObject.dll!FLinkerLoad::ResolveDeferredDependencies() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:768]
UE4Editor-CoreUObject.dll!FLinkerLoad::ResolveAllImports() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:1005]
UE4Editor-CoreUObject.dll!FLinkerLoad::FinalizeBlueprint() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\blueprint\blueprintsupport.cpp:1090]
UE4Editor-CoreUObject.dll!FLinkerLoad::Preload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3190]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3792]
UE4Editor-CoreUObject.dll!FLinkerLoad::IndexToObject() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3982]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3505]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExportAndPreload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2661]
UE4Editor-CoreUObject.dll!FLinkerLoad::LoadAllObjects() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2769]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1032]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3926]
UE4Editor-CoreUObject.dll!FLinkerLoad::IndexToObject() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3976]
UE4Editor-CoreUObject.dll!FLinkerLoad::operator<<() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:4165]
UE4Editor-CoreUObject.dll!UObjectProperty::SerializeItem() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\propertyobject.cpp:32]
UE4Editor-CoreUObject.dll!FPropertyTag::SerializeTaggedProperty() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\public\uobject\propertytag.h:145]
UE4Editor-CoreUObject.dll!UStruct::SerializeTaggedProperties() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\class.cpp:1320]
UE4Editor-CoreUObject.dll!UObject::SerializeScriptProperties() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\obj.cpp:984]
UE4Editor-CoreUObject.dll!UObject::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\obj.cpp:926]
UE4Editor-Engine.dll!USceneComponent::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\components\scenecomponent.cpp:1549]
UE4Editor-Engine.dll!UPrimitiveComponent::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\components\primitivecomponent.cpp:552]
UE4Editor-Engine.dll!USkinnedMeshComponent::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\skeletalmesh.cpp:4909]
UE4Editor-Engine.dll!USkeletalMeshComponent::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\skeletalmesh.cpp:4933]
UE4Editor-CoreUObject.dll!FLinkerLoad::Preload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:3143]
UE4Editor-CoreUObject.dll!FLinkerLoad::CreateExportAndPreload() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2667]
UE4Editor-CoreUObject.dll!FLinkerLoad::LoadAllObjects() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2769]
UE4Editor-CoreUObject.dll!LoadPackageInternal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:1032]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2354]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImportInner() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2402]
UE4Editor-CoreUObject.dll!FLinkerLoad::VerifyImport() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:2115]
UE4Editor-CoreUObject.dll!FLinkerLoad::Verify() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\coreuobject\private\uobject\linkerload.cpp:1905]
UE4Editor-CoreUObject.dll!FLinke
LogClass:Warning: Property AnimGraphNode_ModifyBone_7AE3FA0B49C08555655ED5A0DAA6B455 of ABP_Flag_C has a struct type mismatch (tag AnimNode_ModifyBone != prop FallbackStruct) in package:  D:/Development/Mathias/Papierboot/GameProject/Paperboat/Content/Meshes/Boat/Assets/Meshes/ABP_Flag.uasset. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_574C07AE49C974EB987A2EBD2CC3829B of ABP_Flag_C has a struct type mismatch (tag AnimNode_ModifyBone != prop FallbackStruct) in package:  D:/Development/Mathias/Papierboot/GameProject/Paperboat/Content/Meshes/Boat/Assets/Meshes/ABP_Flag.uasset. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_210B167644B5CEBEF598159E4ABC7B67 of ABP_Flag_C has a struct type mismatch (tag AnimNode_ModifyBone != prop FallbackStruct) in package:  D:/Development/Mathias/Papierboot/GameProject/Paperboat/Content/Meshes/Boat/Assets/Meshes/ABP_Flag.uasset. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_940E3F6242977286E638BABF8FD15E8B of ABP_Flag_C has a struct type mismatch (tag AnimNode_ModifyBone != prop FallbackStruct) in package:  D:/Development/Mathias/Papierboot/GameProject/Paperboat/Content/Meshes/Boat/Assets/Meshes/ABP_Flag.uasset. If that struct got renamed, add an entry to ActiveStructRedirects.
LogAnimation:Warning: Invalid animation root node index 6 on '/Game/Meshes/Boat/Assets/Meshes/ABP_Flag.ABP_Flag_C' (only 3 nodes)
LogAnimation:Warning: Invalid animation root node index 6 on '/Engine/Transient.REINST_ABP_Flag_C_0' (only 3 nodes)
LogClass:Warning: Property AnimGraphNode_ModifyBone_7AE3FA0B49C08555655ED5A0DAA6B455 of ABP_Flag_C has a struct type mismatch (tag FallbackStruct != prop AnimNode_ModifyBone) in package:  FObjectReader. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_574C07AE49C974EB987A2EBD2CC3829B of ABP_Flag_C has a struct type mismatch (tag FallbackStruct != prop AnimNode_ModifyBone) in package:  FObjectReader. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_210B167644B5CEBEF598159E4ABC7B67 of ABP_Flag_C has a struct type mismatch (tag FallbackStruct != prop AnimNode_ModifyBone) in package:  FObjectReader. If that struct got renamed, add an entry to ActiveStructRedirects.
LogClass:Warning: Property AnimGraphNode_ModifyBone_940E3F6242977286E638BABF8FD15E8B of ABP_Flag_C has a struct type mismatch (tag FallbackStruct != prop AnimNode_ModifyBone) in package:  FObjectReader. If that struct got renamed, add an entry to ActiveStructRedirects.

UE 4.9.0 Launcher Version

Hey user37337,

I’d like to get my hands on this issue. Would you be willing to send me your project?

If so, you can upload it to Drive, Dropbox, etc and PM me the link on the forums.

-.

Hey user37337,

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance.

-.

Hi ,

I’m experiencing the same problem since 4.9 when I cook. Unfortunately I will not be able to send the project, but here is a screenshot of my anim graph.

and the error:

LogProperty:Error: UStructProperty::Serialize Loading: Property 'StructProperty /Game/Characters/Temp_Character/Animations/ThirdPersonAnimBlueprint.ThirdPersonAnimBlueprint_C:AnimGraphNode_ModifyBone_4E2FCE734E87E194064A82903A02A287'. Unknown structure.

Can I get some more details about the Modify Bone nodes? What rotation mode and rotation space are you using?

Also, would you be willing to use the migrate functionality to move your AnimBP over to a blank project and send me that?

-.

Hello ,

What is the best way for me to send you my blank project?

Bas

See my original comment about PMing me a link to a cloud storage location.

EDIT: please comment back on this post after sending the link. It helps with tracking the issue.

Hello ,

I’ve send you the link.

Bas

Hi The Barn,

I’d like to clarify that you all mean the option File>Cook Content for Windows OR File>Package Project>DESIREDPLATFORM.

I am completely unable to reproduce this on my end even with your project.

-.

Hello ,

It took a while for me to get back to this problem. I found the reason why it this happens in my project. I get some errors at startup concerning Redirects one of which is:

  • Error ActiveClassRedirects contains a collision with multiple redirectors for old class named AnimNode_ModifyBone

I found this solution: How to solve ActiveClassRedirects error? - Blueprint - Epic Developer Community Forums

I’m not sure however whether or not deleting the ActiveClassRedirects is safe to do.

Bas

I’d create a copy of your project and try it out there so you can see if it works without effecting your working project.