Not all MidPhases are enumerated in TSimCallbackObject::OnMidPhaseModification

UE - Simulation - Core - Dec 2, 2025

Newly generated MidPhases are copied into the array accessible in the NarrowPhase after the OnPreSimulate callback is invoked. As a result, it is not possible to modify newly created MidPhases withi ...

DoDeferredRender will not UpdateBound correctly when NavigationCachedBoundsUpdated

UE - AI - Navigation - Dec 2, 2025

With InstancedStaticMeshComponent, after calling AddInstance, an instance that’s far away gets culled because of additional logic that was added in 5.7 to This works correctly in 5.6 and the instanc ...

Material LocalPosition node does not work correctly with Nanite Skinned meshes

UE - Graphics Features - Dec 1, 2025

Nanite Skinned Meshes don't receive the correct Local Position in some shadow passes. This depends on the clipmap level, and is not related to VSM caching. Unreal Engine 5.6 shows the same issue, b ...

Memory leak in Landscape edit mode

UE - Graphics Tools - Terrain - Landscape - Nov 28, 2025

Initialization error when creating FEventReply objects from Python

UE - Editor - UI Systems - UMG - Nov 28, 2025

the handled value passed to unlock_mouse is actually treated as unhandled, because FEventReply has no uproperty and no Identical()function of its own. Adding WithIdenticalViaEquality can fix this is ...

PIE also rendering in-active / unfocused editor viewport

UE - Graphics Features - Nov 28, 2025

In 5.8, after entering PIE, the editor will start doing two SceneRenders per frame. This dramatically drops performance. Presumably this second render is for the inactive / unfocused editor viewport ...

SaveGeneratedTexture2DAsset can crash when overwriting an existing asset

UE - Texture - Nov 28, 2025

SaveGeneratedTexture2DAsset can crash for a variety of reasons when overwriting an existing texture asset. When no existing asset exists, the function simply moves the provided transient Texture ass ...

Translucent deferred decal materials look different when setting specular attribute directly or via constant node

UE - Rendering Architecture - Materials - Nov 28, 2025

Translucent deferred decal materials look different when setting their specular material attribute directly on the material node versus setting it via a constant node ...

Morph target normals not correctly applied when imported as LOD 0

UE - Editor - Content Pipeline - FBX - Nov 27, 2025

This is a regression since 5.5 with skeletal meshes where morph target normal/tangent deformation only works when a mesh is imported as a LOD of an existing skeletal mesh, but not when imported as L ...

Translucent Wireframe Materials Exhibit TSR Aliasing/Crawling Due To Incorrect Velocity Rendering When Set to Output Depth And Velocity

UE - Graphics Features - Nov 27, 2025

Note that this bug potentially also affects a wide variety of material / geometry setups; however, a translucent wireframe setup is currently the main reproduction case. The issue may also be notice ...