Unexpected Collision Response When Nesting Primitive Components with auto-weld enabled and physics disabled on children. The root primitive falls through floor even though it is set to block all.

UE - Simulation - Physics - May 27, 2025

Context Auto-weld makes it so if a child is attached to a parent, the two bodies will be joined into a single rigid body. Physic settings like collision profile and body settings are determined by t ...

Virtual Shadow Maps on Spot Lights cause a blocky presentation similar to an incorrect mip level

UE - Graphics Features - Shadows - May 26, 2025

Spot Lights may present with very blocky shadow artefacts when a long attentuation radius is provided with a small cone angle. In extreme cases, this causes the VSMs to invalidate every frame. Notab ...

Creating FTickableObjectBase inherited class in async thread may cause pure virtual function call

UE - Framework - May 22, 2025

Classes that inherit from FTickableObjectBase are added to the tickable queue by the QueueTickableObjectForAdd function during their construction (see FTickableGameObject::FTickableGameObject). At t ...

When importing static mesh using interchange and collision is generated, the asset does not have Collision Generated set to true

UE - Editor - Content Pipeline - Import and Export - May 19, 2025

Context: The Interchange Framework is Unreal Engine's import and export framework. When importing a mesh without collision, collision can be auto-generated. Problem: The problem is when importing s ...

Generated instances can not be cleaned up when PCGVolume is copied to a different level

UE - World Creation - Procedural Tools - May 19, 2025

Copying a PCGVolume beyond a level creates an instance that cannot be deleted. In UE5.5 or later, it is possible to delete the instance by pressing Cleanup button with Ctrl key (purge all components ...

[AI] SmartObjectSlot does not have a valid node ref even when it should project to navigation.

UE - AI - SmartObject - May 17, 2025

If you request a SmartObject slot entrance location and require it to be navigable, it will return a result that does not include the node ref of the nav poly for the entrance to the slot. Instead i ...

Cash when entering Path Tracing view mode if r.Decal.NormalReprojectionEnabled true

UE - Graphics Features - Path Tracer - May 16, 2025

Cash when entering Path Tracing view mode if r.Decal.NormalReprojectionEnabled true The licensee has reported: This crash happens because the DeferredShadingRenderer tries to extract the normal GBu ...

Bone names of ~100 characters or longer crash the editor when baking to control rig

UE - Anim - Rigging - Control Rig - May 15, 2025

This is an issue with inconsistencies over rig names and how control names are generated. We expect that a control name will be appended with _CONTROL or _CURVE_CONTROL. But because URigHierarchy: ...

Bug in CurveLinearColor makes colors of Diffraction material white outside curve range, causing rendering artifacts

UE - Texture - May 14, 2025

There seems to be a regression with linear textures (commonly for multi-channel masked textures) in UE5.4. Setting the "Encoding Override" (under Texture > Advanced > Source Color Settings) to "Line ...

Sequence with restore state set is causing a "Fatal world leaks detected" crash

UE - Anim - Sequencer - May 14, 2025

We recently had a few occurrences of crashes caused by a "Fatal world leaks detected" error when unloading a level (in a packaged game and in editor). I tracked down what was keeping a references t ...