UBackgroundBlur crashes at PSO creation under D3D12 SM6 when stereo rendering is enabled

UE - Editor - UI Systems - Slate - Jun 4, 2026

Any Slate widget that triggers the Slate post-process blur (e.g., a UBackgroundBlur with non-zero strength) hits a fatal D3D12 CreateGraphicsPipelineState failure on first render. The fatal is funne ...

Crash in UWidgetAnimation::CreateDirectorInstance when switching resolution

UE - Anim - Sequencer - Jun 2, 2026

Hello, We've encountered a crash in UWidgetAnimation::CreateDirectorInstance when repeatedly switching resolutions. We've had it for a while but it's not until recently that we've found a consisten ...

Instanced Actors: PCG on RuntimeGrid "None" assigns created IAManagers RuntimeGrid "MainGrid", causing cross-grid reference

UE - World Creation - Procedural Tools - PCG Graph - May 30, 2026

Context PCG can be used to spawn Instanced Actors via the PCG IA Interop plugin, that makes Spawned Instanced Actors available as node. When a PCGActor placed in the level runs a PCG graph that spa ...

Backout attempted fix for - AutoSize triggers ensure on shortened Skel Anim Section moved past anim length

UE - Anim - Sequencer - May 29, 2026

In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...

AutoSize triggers ensure on shortened Skel Anim Section moved past anim length

UE - Anim - Sequencer - May 26, 2026

In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...

Lumen lighting in Presentations may appear darker than in Viewport

TM - Rendering - May 22, 2026

Reported in SF [Link Removed] In some scenes with Lumen enabled, interior scene lighting without direct lighting can appear drastically darker in Cloud Presentations than they do in the editor view ...

StreamingGeneration: Actor desc mutator phase now writes ActorDescView directly, breaking the cluster-invariant check in ValidateContainerInstanceDescriptors

UE - World Creation - Worldbuilding Tools - World Partition - May 22, 2026

This report is from an EPS case: We hit a regression upgrading our project from 5.7 to 5.8. Map Check (and any other path that ends up calling UWorldPartition::CheckForErrors) assert inside FWorld ...

FNiagaraRendererMeshes::GetDynamicRayTracingInstances(...) corrupting GPUScene when rendering multiple views

UE - Rendering - Graphics Features - Ray Tracing - May 20, 2026

When rendering a game in splitscreen using Lumen HWRT, Nanite and a large number of Niagara Mesh Particles 1mil+, various meshes and actors will stop rendering. Setting r.RayTracing.Geometry.Niagar ...

[Configuration] Exported Presentations do not adhere to "Visible Configuration" settings and display all Configurations

TM - Tools - May 19, 2026

Reported in SF [Link Removed] Exported Presentations do not respect the "Visible Configuration" settings set for the Presentations and instead display all Configurations regardless of whether they ...