Non-existing config file loading could cause memory leak

UE - CoreTech - Oct 19, 2023

The cause of this problem is the Engine has code paths which register a new allocated object to Map without deleting the previous object. In the repro project, whenever hitting Space Bar, the level ...

Crash when using Property Access node on Animation Blueprint (repro based on Lyra Starter Game animation layers)

UE - Anim - Runtime - Jan 24, 2024

When using the Property Access node on Animation Blueprints to gain performance by better exploring parallel processing, it is possible that the underlying accessed property or any intermediate acce ...

Fracture Mode > "Remove-On-Break" setting: Cluster Crumbling causes flickering

UE - Simulation - Physics - Destruction - May 10, 2025

Fracture Mode > "Remove-On-Break" setting: Cluster Crumbling causes flickering. Once the Remove-On-Break Cluster Crumbling effect is activated, there is a small delay between the disappearance of th ...

Crashes when attempting to use an Instanced Struct inside Control Rig / Rig VM

UE - Anim - Rigging - Control Rig - Mar 17, 2025

Currently, the Control Rig Editor allows the user to use the "Instanced Struct" type, for example for a variable or function input/output. However, this type does not seem to be properly supported ( ...

Deadlock when running an asset validator commandlet with async skeletalmesh build

UE - Editor - Content Pipeline - Asset Build - Mar 10, 2023

[External Code]   UnrealEditor-Core.dll!FEventWin::Wait(unsigned int WaitTime, const bool bIgnoreThreadIdleStats) Line 1515 C++   UnrealEditor-Engine.dll!FAsyncTaskBase::WaitCompletionWithTimeout( ...

GameplayAbility Blueprint's FGameplayAttribute does not retain value reference upon Compile

UE - Gameplay - Sep 17, 2019

GameplayAttribute-type function arguments in BP-callable functions(I.E a Blueprint event graph) or nodes have their value reset on BP compilation ...

When rendering a reflection capture, the lightmap may be rendered without finishing streaming.

UE - Graphics Features - Oct 5, 2021

This problem occurs when you do a lighting build. It does not occur when the reflection capture is done by itself. ...

Puzzle template blocks turn gray when hovered over in Code version vs no reaction in BP version

Docs - Samples - Feb 3, 2017

Functionality is different between code and bp versions of the puzzle template ...

FInstancedStruct does not serialise to JSON when used in a DataTable

UE - Editor - Workflow Systems - Aug 4, 2025

The JSON export functionality for DataTable relies on a FieldIterator to gather properties. This iterator is unable to gather the properties from the InstancedStruct. CSV export functionality works ...

Crash in IndirectLightingCache on level load

UE - Graphics Features - Aug 11, 2016

May be a duplicate of this bug, which was closed due to no repro:https://jira.ol.epicgames.net/browse/UE-10978 ...