Unreal Engine Issues
Unreal Engine Issues
Virtual Memory leak when using specific rendering settings in the template project
UE - Rendering - Architecture - RHI - Dec 20, 2025When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...
Skeletal Mesh BLAS updates when not animating
UE - Rendering - Architecture - RHI - Dec 19, 2025The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...
Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor
UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...
Editor localization causes the GetLinkedAnimLayerInstanceByGroup function to fail in retrieving the corresponding LinkedAnimLayer within the editor.
UE - Anim - Runtime - Anim Blueprints - Dec 18, 2025When using other language(such as Chinese) as editor language, the Group Name of the Animation Interface will be localized to Chinese. In editor, the animation blueprint grab the group from metadata ...
If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.
UE - Framework - Blueprint Editor - Dec 17, 2025Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...
[WorldPartition][CellTransformer] ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack
UE - World Creation - Worldbuilding Tools - World Partition - Dec 17, 2025There is a risk of actor components registering with the wrong world when reconstructed from UWorldPartition::ApplyRuntimeCellsTransformerStack. The repro case is arguably a bad usage, but it was th ...
A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction
UE - Simulation - Gameplay - Dec 16, 2025Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...
Paper2D: Editor hangs when assigning Sprite Atlas Group to Sprite
UE - Gameplay - Paper2D - Dec 16, 2025In UE 5.3 and later, assigning a Sprite Atlas Group to a UPaperSprite asset can cause the editor to hang and eventually crash. This behavior has been reproduced in 5.3, 5.6, and a recent UE5-main so ...
Convex hull generation fails when first 3 verts are colinear
UE - Simulation - Core - Dec 9, 2025The licensee identified a number of cases where loading assets will trigger convex hull generation warnings:If the first 3 verts in the set are colinear (in which case IsPlanarShape() returns true b ...
Drag and Drop fails in Standalone and Packaged builds when WidgetComponent’s Widget is set at runtime
UE - Editor - UI Systems - Dec 4, 2025When a UWidgetComponent has its widget assigned dynamically at runtime using CreateWidget and SetWidget, drag & drop operations fail in Standalone Game and packaged/game builds, while working correc ...