Editor becomes unresponsive for long periods between edits of a user-defined enum type when it's referenced by one or more user-defined struct types.

UE - Gameplay - Blueprint - May 17, 2021

After adding a member to a user-defined struct type and changing the member type to a user-defined enumeration, repeated edits to that enumeration will eventually cause the editor to become increasi ...

Instanced Stereo setting crashes engine when building lighting, creating a vector3 or disabling setting

UE - Platform - XR - Apr 4, 2022

After further investigation we noticed that the issue is arising from the Instanced Stereo setting. When creating a Vector3 in a new material, building lighting or disabling the Instanced Stereo set ...

Generate all Bodies on Selected Bones Does Not Generate Single Convex Hulls Uniformly

UE - Simulation - Core - May 12, 2022

Occurs 5/5 Times Regression does not occur in //UE4/Release-4.27.2 @ CL 18319896 When 'Generating All Bodies' on a bone the single convex hull does not generate uniformly.  ...

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 ...

[MetaSounds][Audio Bus] - MetaSound Sources using Audio Bus nodes spam underruns when Audio Mixer Sample Rate is less or greater than 48kHz

UE - Audio - Audio Bus - Oct 5, 2023

Setting the Audio Mixer Sample Rate to 32000kHz causes underrun spam in audio bus reader and writer nodes and sounds to playback jittery. Tested with 24kHz and 32kHz. Does not repro in //Fortnite/R ...

MakeArray wildcard node gives a compilation error when being used in a Blueprint Macro.

UE - Framework - Blueprint - Dec 19, 2024

There is an error with the SmartMacroInterface, where you can't use an empty wildcard "Make Array" node. This error makes the blueprint not compile and the macro unusable. Disabling the bUseSimpleWi ...

When a TSoftObjectPtr pointing to a const type is used as a parameter for a Dyanmic delegate, unreal marks it as deprecaded.

UE - Foundation - Cpp Tools - UnrealHeaderTool - Jan 21, 2025

A change has been done to the TSoftObjectPtr class that warns when constructing a pointer-to non-const from a pointer-to-const. This change makes sense and is correct. Example: UTexture2D* Loade ...

Sphere Reflection Captures overridden by Skylight

UE - Graphics Features - Jun 10, 2025

When using non-Lumen lighting and Screenspace reflections off, the skylight location overrides the Reflection Capture location during Build Reflections. This results in a Reflection Capture taken fr ...

ULevelSequence trying to duplicate a REINST_ class when creating new custom binding in ConvertOldSpawnables()

UE - Framework - Blueprint Compiler - Jul 23, 2025

The assert that we're hitting is:Cannot replace existing object of a different class.  New Object: /Engine/Transient.REINST_BPC_NPC_VFX_C_230 /Game/Maps/[REDACTED]/Levels/[REDACTED]/LevelSequence/ ...