Crash after creating a suboject for RootComponent if the actor is placed on the level

UE - Foundation - Cpp Tools - Hot Reload - Nov 6, 2020

The crash occurs when trying to assign a new value to RootComponent if the Pawn is already placed on the level Crash does not happen in  P4 //UE4/Release-4.25.3 CL 13942748 Other steps to reproduc ...

Niagara Scalability Crash When Processing Significance

UE - Niagara - Jun 4, 2025

Method FNiagaraScalabilityManager::ProcessSignificance() iterates on indices from Context.SignificanceIndices and uses them to access the State and ManagedComponents arrays. It can then decide to cr ...

Virtual Memory leak when using specific rendering settings in the template project

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

When 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 ...

DOF - TAA pass ghosting when using r.DOF.TAA.CoCBilateralFilterStrength

UE - Graphics Features - Aug 7, 2025

In Unreal 5.6, there's a new CVar: r.DOF.TAA.CoCBilateralFilterStrength, which should help with ghosting artifacts introduced by TAA in DOF passes. However, it doesn't work as expected since many gh ...

Crash Importing Skeletal Mesh LODs with a lot of morph targets

OLD - Anim - May 18, 2016

Crash Importing Skeletal Mesh LODs with a lot of morph targets Error message: Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 785] Array index out of bounds: 2 from an ar ...

Crash related to Vertex Painting - MeshPaint!CastChecked<AActor,UObject>()

Tools - May 23, 2016

This crash was reported on the UDN. Upon further investigation it has been experienced by a handful of different users throughout 4.11 and 4.12. JIRA logged for tracking despite unknown repro steps ...

Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling

UE - Rendering - Graphics Features - Jan 12, 2026

At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...

FBX Camera Import into Sequencer - Scale Does Not Apply to Scene-Dependent Attributes (e.g., Focus Distance)

UE - Anim - Sequencer - May 1, 2025

When importing an FBX camera into a Level Sequence via the FBX Import dialog, we rely heavily on the Import Uniform Scale and Convert Scene Unit options for DCC interoperability. These settings ...

Crash after setting a key on a Rotation Track, then trying to right click the key with Transform track collapsed

UE - Anim - Sequencer - Aug 3, 2016

Error message: Access violation - code c0000005 (first/second chance not available) Source Context: 336 337 if (bHasRotationKeys) 338 { 339 TSharedRef<FStru ...

Incorrect behavior after attaching an actor to a non-root component of another actor in the Editor

UE - Editor - Workflow Systems - Jul 3, 2024

UE allows actors to be attached to other actors. More precisely, it allows the root component of an actor (child) to be attached to any component of another actor (parent). From now on, "parent" and ...