Saving Behavior Tree with Blueprint task inheriting from native class invalidates Blackboard key when BP contains a function

UE - AI - Jul 8, 2025

A regression introduced in UE 5.6 causes Blackboard key selectors in Blueprint tasks to become invalid when the Blueprint inherits from a native subclass of UBTTask_MoveTo (or UBTTask_BlackboardBase ...

Assigning a static mesh to a Mutable Clip Mesh With Mesh Node can crash the editor

UE - Anim - Mutable - Jul 4, 2025

Context: The Mutable plugin has a modifier node called Clip Mesh With Mesh that allows Static Mesh modifiers to be assigned as the clip mesh. Under certain circumstances, an assert can be triggered ...

Sequencer - When a subsection has negative play rate, any nested sub-subsections fail to evaluate

UE - Anim - Sequencer - Jul 3, 2025

Consider a sequence hierarchy with more than two layers. If the top-level sequence uses a negative timescale on a sub-sequence, the contents inside it animate as expected, but any nested sub-sequenc ...

PCG crash when using Attribute Remove Duplicates on partitioned data if one of those sets of data is empty

UE - World Creation - Procedural Tools - PCG Graph - Jul 3, 2025

Context: In PCG, the Attribute Remove Duplicates node can be used to remove duplicate attributes from an array. Problem: The licensee has observed that using the Attribute Remove Duplicates node ...

CPU Lightmass generates different lighting results on a landscape if executed via a commandlet vs through the editor

UE - Graphics Features - Jul 3, 2025

Building lighting via commandlet and via editor are giving different results. To prevent one method from polluting the other via Swarm cache, the cache needs to be cleared in between tests. ...

Inconsistent Details Panel Focus Behavior On Enter Pressed for Blueprint-Added Components

UE - Editor - Workflow Systems - Jul 2, 2025

When editing a component property in the level viewport, if the component was added via the Blueprint Editor, pressing Enter after changing a value causes the details panel to lose focus. This inter ...

In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled

UE - Simulation - Physics - Destruction - Jun 30, 2025

In a Geometry Collection, enabling Nanite Fallback in a Nanite Enabled collection won't generate a Physics Body when Nanite is disabled. To verify this, follow the steps provided in the Steps to Re ...

Sphere Mask ArgInvHardness missing multiplication

UE - Rendering Architecture - Materials - Jun 27, 2025

Hi Epic, In MaterialExpressions.cpp UMaterialExpressionSphereMask::Compile(), hardness is not calculated the same way in both <if> conditions. One is missing a multiplication by 0.01f. Specificall ...

Water Body Custom generates Map Check Warnings

UE - Graphics Tools - Terrain - Water - Jun 26, 2025

From licensee: Water Body Custom Actors generate this warning during Map Check: WaterBodyCustom_UAID_507C6F36B9215C5B02_1871778061 Static mesh actor has NULL StaticMesh property. To reproduce, si ...

In Sequencer, copying a Missing/Invalid Bound Object to a track may crash the Editor with an Unhandled Exception at UExporter::FindExporter()

UE - Anim - Sequencer - Jun 26, 2025

In Sequencer, copying a Missing/Invalid Bound Object to a track may crash the Editor with an Unhandled Exception at UExporter::FindExporter(). The licensee has provided a txt file that contains the ...