Landscape Textures Patches issue when using "Texture Backed Render Target" as the Height Patch Source Mode where Landscape patches are not applying properly the first time a level is opened after restart

UE - Graphics Tools - Terrain - Landscape - Oct 6, 2025

Context: Landscape patches are components that can be attached to meshes to affect the landscape as the mesh is repositioned. Problem: The problem is that when using "Texture Backed Render Target" ...

Lumen ignores Landscape Holes (Landscape Visibility) when Hardware Ray Tracing is enabled and Ray Lighting Mode is set to Surface Cache

UE - Rendering - Graphics Features - Ray Tracing - Jan 31, 2025

Context Lumen is the default global illumination and reflections system. Lumen renders diffuse interreflection with infinite bounces and indirect specular reflections in large, detailed environments ...

Switching modular control rig to FK mode breaks pose of controls that have been baked to rig

UE - Anim - Rigging - Control Rig - Sep 14, 2025

From the licensee:We have built a modular Control Rig in Unreal 5.6, and while IK to FK matching works correctly inthe rig, but we are facing an issue when applying mocap animation to the characters ...

Crash when calling FillDataTableFromCSVString() while viewing the contents of the data table

When the function UDataTableFunctionLibrary::FillDataTableFromCSVString() is used from Editor Utility Blueprints or Python Scripts, and the contents of the affected Data Table are currently being vi ...

BoneList and BoneFilterActionOption in LOD0 of LODSettings are displayed after editing other LOD level

UE - Runtime - Animation - Jul 31, 2023

BoneList and BoneFilterActionOption in LOD0 of LODSettings are filters by the following code. void FSkeletalMeshLODSettingsDetails::CustomizeDetails(IDetailLayoutBuilder& LayoutBuilder) { ... st ...

Missing PSO Precaches in the engine

UE - Rendering - Architecture - RHI - Aug 20, 2025

A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...

Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.

UE - Rendering - Architecture - Materials - May 30, 2025

In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...

Audio Memory Growth While Paused

UE - Audio - Feb 26, 2026

User has provided a trace file attached to case. User experiencing going out of memory during gameplay with console command "Pause" activated. Using 5.6 from Perforce in the Release-5.6.0 stream at ...

Resavepackages commandlet strips level package thumbnails

UE - Editor - Developer Usability - May 12, 2026

When loading thumbnails in FLinkerLoad::SerializeThumbnails, the level asset has two thumbnails. The first one has a size of 0, which causes the loading process to abort early. Since the actual thum ...

Changes to Instanced Properties default value on BP not propagated to placed actors in the opened level

UE - Core - Systems - May 15, 2025

In UE versions 5.4 and onwards (as of CL 42589677 in Main), when an Instanced UObject property is defined in an Actor Blueprint, modifying the default value in the Blueprint does not propagate the c ...