FBlackboardKeySelector filters aren't applied when recompiling blueprint if a behavior tree asset containing the blueprint added as a service is closed, or if the blueprint is reparented.

UE - AI - BehaviorTree - Sep 24, 2025

Context In Behavior Trees, BT Services can be added to nodes. Those services can have configurable FBlackboardKeySelectors. BlackboardKeys are variables on a blackboard that the behavior tree can r ...

Post Process Animation Blueprint Crash When Using Blend Node

UE - Anim - Runtime - Anim Blueprints - Sep 24, 2025

When using a Blend node inside a Post Process Animation Blueprint, the editor crashes while rendering thumbnails. The crash occurs because USkeletonThumbnailRenderer attempts to draw a thumbnail wit ...

Mutable constant texture variable with ClipUV mask only works with new experimental dynamic variable is connected as well

UE - Anim - Mutable - Sep 22, 2025

We are attempting to use Mutable in 5.6.1 and have encountered an issue which we are not sure how to resolve. The issue occurs when using the ClipWithUVMask node. In short we have a customizable o ...

Applying downscale causes textures to display unexpectedly on widgets

UE - Editor - UI Systems - Slate - Sep 22, 2025

When applying downScale 2.0 to UI textures to reduce resolution, unintended display issues occur on widgets, such as: ・The border of box-shaped Widgets with DrawAs set to “Box” becomes thinner ・Dot ...

In 5.6, bWarningsAsErrors does not work with clang

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 20, 2025

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes:    [WarningsClangToolChain(["-Wno-date-time"], ["-Wdate-time", "-Wno-error=date-ti ...

Ray tracing scene doesn't reflect WPO with instance custom data

UE - Graphics Features - Ray Tracing - Sep 19, 2025

When custom instance data is used to calculate WPO in a Material and applied to an ISM the WPO value in the Lumen scene (ray tracing scene) is different than the visible scene resulting in incorrect ...

Mutable custom versioning issue from 5.5->5.6

UE - Anim - Mutable - Sep 19, 2025

In 5.6, a handful of new entries in `FCustomizableObjectCustomVersion` were added, including `SetDisplayNamePropertyAsPinNameOfTableNodes`. Looking back at the history, `SetDisplayNamePropertyAsPinN ...

Mutable references MetaHumans heads directly, but DNA Assets are private

UE - Anim - Mutable - Sep 18, 2025

When we switched our project to 5.6.1 This error appeared on build. The compilation of the Mutable assets in the editor is not reporting any issue. ...

Seam visible when using a material with BumpOffset on a Nanite mesh

UE - Graphics Features - Nanite - Sep 18, 2025

When a material that uses BumpOffset is fed into the Emissive Color of Surface Opaque Default Lit material and then applied to a nanite mesh, a visible seam can be seen along edges and the intersect ...

Setting a struct bool property (bitfield) to itself writes the wrong value

UE - Framework - Blueprint Compiler - Sep 17, 2025

There's an issue when assigning a bitfield bool to a native bool in Blueprints. Currently, the engine erroneously treats the memory for a local bool as a uint8 bitfield, which is undefined behavior. ...