WorldToClip/ClipToWorld transform in materials not behaving as expected

UE - Graphics Features - Dec 19, 2025

In 5.3, the specified code will return all 0 or very small as expected. However in 5.4.4 and onwards (also checked in 5.6.1 & 5.7.1), it returns very large numbers. ...

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

UE - 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 ...

Area scattering defaults to 0.01 spacing when input is invalid

TM - Tools - Dec 18, 2025

If the user provides an invalid input for Area spacing (for example, using the hotkey 'R' to check the raytraced image), the spacing defaults to a value of 0.01m. Depending on the size of the Area s ...

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

UE - Graphics Features - Substrate - 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 ...

Editor localization causes the GetLinkedAnimLayerInstanceByGroup function to fail in retrieving the corresponding LinkedAnimLayer within the editor.

UE - Anim - Runtime - Anim Blueprints - Dec 18, 2025

When using other language(such as Chinese) as editor language, the Group Name of the Animation Interface will be localized to Chinese. In editor, the animation blueprint grab the group from metadata ...

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 ...

Unable to interact or collide with geometry collection after Removal on Sleep or Break timer finishes, yet unbroken piece continue to render

UE - Simulation - Core - Dec 18, 2025

Context: A static mesh is able to have a geometry collection generated from it using the Fracture editing mode. It can be fractured in many different ways, and when acted upon by a chaos field agent ...

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 ...

Section::TrimSection resulting in bad key values at start and end of trim range

UE - Anim - Sequencer - Dec 17, 2025

The trim process inserts keys at the start or end of the range depending if you specify Trim Left or Right, I'm finding that Trim right is inserting a key at the end of the section that is incorrect ...

ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack

UE - World Creation - Worldbuilding Tools - World Partition - Dec 17, 2025

There is a risk of actor components registering with the wrong world when reconstructed from UWorldPartition::ApplyRuntimeCellsTransformerStack. The repro case is arguably a bad usage, but it was th ...