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 ...

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 ...

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 ...

Changing MaterialQualityLevel causes a crash due to a ShaderMap mismatch in UniformExpressionCache

UE - Rendering Architecture - Materials - Nov 26, 2025

A crash may occur when changing the MaterialQualitylevel via Scalability due to a race condition. The issue occurs because in ScalabilityCVarsSinkCallback(), when it creates the FGlobalComponentRec ...

Dataless Mutable: Cloth Simulation Not Working With Skeletal Mesh Parameter Node?

UE - Anim - Mutable - Nov 25, 2025

Testing the new dataless Mutable workflow in Unreal Engine 5.7. When replacing the old Skeletal Mesh node with the new Skeletal Mesh Parameter node, the cloth simulation stops working. ...