Unreal Editor can get in an infinite while loop when checking the History of an asset under Perforce.

UE - Editor - Workflow Systems - Oct 21, 2024

Unreal Editor can get in an infinite while loop when the action Asset->Source Control->History is used in a Blueprint Asset. Reportedly, this issue is only encountered when using the Branches featur ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

UE - Rendering Architecture - Materials - Oct 31, 2024

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

A Geometry Collection with Removal-On-Break, after breaking and shrinking until vanished, will reset to the original state (full-size and unbroken) if we toggle between Fullscreen and Windowed while playing as standalone or Packaged Build.

UE - Simulation - Physics - Destruction - Oct 28, 2024

A Geometry Collection with Removal-On-Break, after breaking and shrinking until vanished, will reset to the original state (full-size and unbroken) if we toggle between Fullscreen and Windowed while ...

Property Editors fail to import text values for FKeys within array/set/map containers when the key is identified by some valid non-alphanumeric characters

UE - Gameplay - Input - Oct 28, 2024

The FKey structure represents a user action input such as a keyboard key, a mouse button/wheel, or a gesture in VR. For the keyboard, it can represent any pressable key, such as letters, numbers, sy ...

Blueprint function-local variable properties don't copy metadata from the source FBPVariableDescription

UE - Framework - Blueprint Compiler - Jan 23, 2025

FKismetCompilerContext::CreateUserDefinedLocalVariableForFunction() does not copy the metadata from the source FBPVariableDescription entry. Class variables work because there is code for that in FK ...

Lumen ignores Landscape Holes (Landscape Visibility) when Hardware Ray Tracing is enabled and Ray Lighting Mode is set to Surface Cache

UE - Graphics Features - Ray Tracing - Jan 31, 2025

Context Lumen is the default global illumination and reflections system. Lumen renders diffuse interreflection with infinite bounces and indirect specular reflections in large, detailed environments ...

AllowAsyncRenderThreadUpdatesEditorGameWorld/AllowAsyncRenderThreadUpdatesEditor CVars are off by default and unsafe in Niagara

UE - Niagara - Mar 4, 2025

This user made a github pull request: [Link Removed] but it was auto rejected. I think that we can consider taking their fixes, but keeping it disabled by default. ...

When using Perforce, saving a level over another leaves the target umap file as "marked for delete"

UE - Editor - Workflow Systems - Mar 11, 2025

When working on a level asset and using command "File – Save Current Level As..." to save it over a different level asset, the engine first deletes the target level (that's going to be overwritten) ...

Moving a saved duplicate of an OpenWorld level crashes the Editor

UE - World Creation - Worldbuilding Tools - Mar 19, 2025

Moving a saved duplicate of an OpenWorld level crashes the Editor. The act of moving the duplicated OpenWorld level crashes the Editor the moment the engine tries to delete the original level, so it ...

Crash when exposing a TOptional<FName> or TOptional<FText> to the editor through a UProperty.

UE - Editor - Workflow Systems - Mar 25, 2025

Support for editor-exposed uproperties of type TOptional<T> has been added by CL 28199740 on september 2023. However, since then until today in UE 5.5, a crash can happen when exposing TOptional<FNa ...