Subobject ComponentClass overrides cause failing assertions due to UObject reconstruction on AsyncLoadingThread

UE - Engine Scaling - dSTM - Dec 19, 2025

Context The blueprint editor allows you to override an actor component's class in derived blueprints (component details panel -> Component Class). [Image Removed] Problem When a blueprint and it ...

Call In Editor functions not working in blueprints

UE - Editor - Developer Usability - Dec 19, 2025

Context When selecting a component on an actor, any CallInEditor functions on the component's class appear as buttons in the details panel. Problem The CallInEditor functions don't execute in Blu ...

Actor Components incorrectly appearing mixed with the Scene Component Hierarchy in the Component Tab of the Blueprint Editor

UE - Framework - Blueprint Editor - Dec 19, 2025

This is a regression introduced by CL 45871568 in ue5-main branch. The new function FFBlueprintEditorDefaultSortUICustomization::SortSubobjectData() in file "BlueprintEditorSCSEditorUICustomization. ...

Reflections of Masked Materials incorrect with Lumen HWRT and Max Refraction Bounces > 0

UE - Rendering - Graphics Features - Lumen - Dec 18, 2025

Lumen HWRT Reflections of Masked Materials are incorrect when "r.Lumen.Reflections.HardwareRayTracing.Translucent.MaxRefractionBounces" is greater than 0. The same issue occurs if the Post-Process V ...

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

Substrate's coverage node does not skip unlit emissive part which have no coverage

UE - Rendering - Features - Shading Models - Dec 18, 2025

Substrate's coverage node doesn't seem to cull masked pixels of unlit emissive slabs. This is an important optimization when using masked unlit particles. When using a lit slab, the instructions for ...

Cooker is asserting in Class.h on UE 5.7.1

UE - CoreTech - Dec 18, 2025

From the linked EPS case: ---------------------------- In UE 5.7 there were some changes to how Enum member names are stored. This change introduces an assert when cooking using the Editor Debug e ...

If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.

UE - Framework - Blueprint Editor - Dec 17, 2025

Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...

Viewport stuttering during orbit/zoom navigation

UE - Rendering - Graphics Features - Dec 17, 2025

Received a report of persistent stutters in the editor when trying to navigate in the viewport, including asset editor viewports like the Skeletal mesh editor and control rig editor. Hardware used ...

A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction

UE - Runtime - Character - Dec 16, 2025

Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...