Incorrect Lumen Scene direct lighting when objects behind masked landscape

UE - Rendering - Graphics Features - Lumen - Oct 5, 2025

When objects are placed behind or beneath a masked landscape and r.Lumen.HardwareRayTracing.SurfaceCacheAlphaMasking is enabled, the direct light evaluation is incorrect. There are two workarounds, ...

Blueprint actors can not be casted until they have been opened after migration or being upgraded to a more recent engine version

UE - Framework - Blueprint - Jan 5, 2023

This is not a regression tested in //UE5/Release-5.0 CL20979098 After migrating an asset from an older engine version or upgrading a project to newer version Blueprints carried over can not be cast ...

Crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() when quickly unloading then loading a sub-world partition

UE - World Creation - Worldbuilding Tools - Data Layers - Mar 6, 2025

From licensee: Since we integrated 5.5, we are experiencing a crash in AWorldDataLayers::InitializeDataLayerRuntimeStates() on this line check(ActiveDataLayerNames.IsEmpty() && LoadedDataLayerN ...

GenerateKDopAsSimpleCollision() clamps vertices that are close to the origin which results in inaccurate primitives

UE - Gameplay - Nov 10, 2015

When DOP simplified collision is generated for a mesh that has vertices that are close to the origin, part of the function till clamp any values between -0.5 and 0.5 to be 0.5 which will cause the r ...

Crash when adding Actor Components to a Spawnable Actor in Sequencer while it is despawned

zComponent - Archive - Feb 26, 2026

After migrating our project from UE 5.5 to 5.7, we are experiencing a consistent engine crash in the Sequencer. The crash occurs specifically when a user attempts to add a component to a Spawnable A ...

Linux Native Toolchain depends on libninfo5 which is not bundled

UE - Platform - Linux - Sep 6, 2019

libtinfo.so.5 => /lib/x86_64-linux-gnu/libtinfo.so.5 (0x00007fc27cf4d000) bschaefer@bschaefer-Precision-T7600:bin$ ldd ./clang linux-vdso.so.1 => (0x00007ffceefe3000) libpthread.so.0 => /lib/ ...

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine

UE - Runtime - Animation - Jan 22, 2026

Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine with a "Cannot replace existing object of a different class" message. The conditions to re ...

Merge Actors (Simplify) is broken with Substrate Shader Models Node

UE - Rendering - Features - Shading Models - Sep 29, 2025

Substrate Materials cannot be baked when Meshes are merged using the "Simplify" method. All textures except for the normal are reduced to a single black parameter. The normal texture produced does n ...

Enabling Strip Source Data On Cook on Geometry Collection is also stripping the Anchor flag of cooked assets

UE - Runtime - Simulation - Jul 20, 2025

Enabling Strip Source Data On Cook on Geometry Collection (GC) is also stripping the Anchor flag of cooked assets. The licensee has reported that once they do a build the Anchors disappear and GCs t ...