HideBoneByName translates bone to parent which breaks skinning

UE - Runtime - Animation - Jul 30, 2024

Calling HideBoneByName on a bone causes that bone (and all it's children) to be translated to the parent bone's location.  This code in UpdateRefToLocalMatricesInner is responsible: bool bNeedToHid ...

Landscape has a seam when scale is set to a decimal

UE - Graphics Tools - Terrain - Landscape - Jan 13, 2023

Regression: Tested in UE5/Release-5.0 at CL 20979098, this issue does occur so it is not a regression. This issue occurs if the scale set for the landscape has a decimal value that is not 0.5. Sett ...

FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game

UE - Rendering - Architecture - RHI - Jan 7, 2026

When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...

Custom expression additional outputs don't work when connected to World Position Offset

UE - Rendering - Architecture - Materials - Jun 24, 2026

Custom expression additional outputs are considered (0,0,0) when connected to WPO. ...

Open Formats: Reimport PIE - Reimporting an asset during PIE overwrites the bAllowCPUAccess value to true

UE - Editor - Content Pipeline - Import and Export - May 22, 2025

When reimporting a static mesh asset before PIE execution, the value of bAllowCPUAccess is false.  If reimporting a static mesh asset while PIE is running, the value of bAllowCPUAccess is true. In a ...

Missing UV Clamping or Clear in SunAlphaPS_Mobile

UE - Platform - Mobile - Graphics - Nov 13, 2025

In: void SunAlphaPS_Mobile( float2 InUVs[8] : TEXCOORD0, in FStereoPSInput StereoInput, out HALF_TYPE OutColor : SV_Target0 ) { OutColor =  SunUnBias(SunShaftAndDofTexture.Sample(SunShaftAndDo ...

Incorrect config property serialization for UStructs used as TMap keys or contained in a TSet with a single value. Diffs taken from default-value of each member type, instead of from default-value of the struct

UE - Core - Systems - Nov 18, 2024

Consider a UStruct with some basic type members, each one with a default value specified in the struct. Also consider a TSet or TMap with that struct as keys, used inside a UObject as a UProperty an ...

Sphere Mask ArgInvHardness missing multiplication

UE - Rendering - Architecture - Materials - Jun 27, 2025

Hi Epic, In MaterialExpressions.cpp UMaterialExpressionSphereMask::Compile(), hardness is not calculated the same way in both <if> conditions. One is missing a multiplication by 0.01f. Specificall ...

[CrashReport][GPU Crash] NodeAndClusterCull

UE - Rendering - Features - Nanite - Nov 19, 2024

Users affected: 51 Total occurrences: 90 Last occurrence: November 19th 2024, 3:25:41 am First occurrence: August 7th 2024, 8:10:10 pm Latest version: ++UE5+Release-5.5-CL-37670630 Platform: Win64 [ ...

GAS: Duration GameplayEffects applying same GameplayCue tag will on authority end all on-going GameplayCueNotifies when first cue expires

UE - Gameplay - Gameplay Ability System - Aug 16, 2024

When multiple duration GameplayEffects apply a GameplayCue with the same tag, the network authority game instance (standalone & servers) will remove all GameplayCues with that tag from the AbilitySy ...