In editor, sub level instance's streaming state persists incorrectly after toggling Level Behavior without saving

UE - World Creation - Worldbuilding Tools - Level Instances - Jun 11, 2025

When adding a sub level with world partition streaming to a main level where the streaming is also enabled, setting* Level Behavior* of the sub level to Standalone, and saving the result, in the fir ...

Incorrect NiagaraSystem passed to KillUnusedComponents in ReclaimWorldParticleSystem

UE - Niagara - Jun 10, 2025

In UNiagaraComponentPool::ReclaimWorldParticleSystem, the cleanup loop for WorldParticleSystemPools calls KillUnusedComponents with the reclaimed component's NiagaraSystem (Asset) instead of the sys ...

Staging a patch does not copy pak signatures when staging

UE - Foundation - Jun 10, 2025

When creating a patch with pak signing enabled the created output folder contains the pak files from the base release but does not contain the .sig files, even if they were enabled when creating the ...

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 ...

Anim State Notifies Don't Consistently Fire Begin/End Events for Looping Anim Sequences

UE - Anim - Runtime - Anim Blueprints - Jun 9, 2025

If you have an Animation Notify State and set it up on an animation to start at the exact beginning of the anim sequence and finish exactly at the end (I have attached a picture of this). It doesn't ...

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 ...

StructUtils plugin's `FInstancedStruct` in a CPP-defined struct in a `TArray` on an actor component defined in CPP and implemented in BP. Populating the instanced struct in an actor BP's class defaults breaks serialization of the class defaults.

UE - AI - May 30, 2025

Context Instanced structs are great for holding simple data with the main advantage they have is a low memory overhead unlike instanced objects. Problem The problem is in StructUtils plugin's `FIns ...

Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.

UE - Rendering Architecture - Materials - May 30, 2025

In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...

PlayerCameraManager->OnBlendComplete() delegate not getting called

UE - Gameplay - Gameplay Cameras - May 29, 2025

The PlayerCameraManager->OnBlendComplete() delegate is not getting called when running a game in a standalone network mode without any networking. ...

Enabling Wireframe Mode along with HDR (EyeAdaptation) Visualization crashes the Editor

UE - Graphics Features - May 29, 2025

In the Viewport, enabling Wireframe Mode (ALT+2) along with HDR (EyeAdaptation) Visualization crashes the Editor. I've tested different versions and this issue is not present on 5.0, but it reproduc ...