Unreal Engine Issues
Unreal Engine Issues
Mutable Dataless Generation - Regenerate Imported Models Crash
UE - Anim - Mutable - Jun 8, 2026Crash when working with Dataless Mutable content. When selecting meshes in the instance, there is a crash in RegenerateImportedModels. ...
Niagara NDC GPU Instance Counter leak
UE - Niagara - Jun 5, 2026In NiagaraDataChannelData.cpp, FNiagaraDataChannelDataProxy::EndFrame enqueues a GPU readback for each entry in PendingGPUReadbackBuffers, but the corresponding FNiagaraGPUInstanceCountManager::Free ...
Crash in UWidgetAnimation::CreateDirectorInstance when switching resolution
UE - Anim - Sequencer - Jun 2, 2026Hello, 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 ...
Backout attempted fix for - AutoSize triggers ensure on shortened Skel Anim Section moved past anim length
UE - Anim - Sequencer - May 29, 2026In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...
Assert crash when playing Groom Cache with Card Mesh LOD
UE - Rendering - Graphics Features - May 29, 2026Playing a Guides Groom Cache while Card Mesh LOD (Guide-Based) is active causes an assert in RunHairStrandsInterpolation_Cards when the renderer switches to Card LOD. Assert location:Plugins/Runtim ...
Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances
UE - Rendering - Graphics Features - Ray Tracing - May 28, 2026When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...
Sequencer: Expansion State of Animation Track Properties is not saved
UE - Anim - Sequencer - May 26, 2026The expansion state of Animation Track properties is only saved when Section > Advanced is expanded or collapsed.` ...
AutoSize triggers ensure on shortened Skel Anim Section moved past anim length
UE - Anim - Sequencer - May 26, 2026In Sequencer, calling "Edit > Auto Size" on a UMovieSceneSkeletalAnimationSection triggers the LowerBound > UpperBound ensure in UMovieSceneSection::SetRange (MovieSceneSection.h:333) when the secti ...
FNiagaraRendererMeshes::GetDynamicRayTracingInstances(...) corrupting GPUScene when rendering multiple views
UE - Rendering - Graphics Features - Ray Tracing - May 20, 2026When 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 ...
ApplyLocalExposure uses Output_ExtentInverse instead of Output_ViewportSizeInverse for bilateral grid UV
UE - Rendering - Graphics Features - May 18, 2026The ApplyLocalExposureCS shader in PostProcessLocalExposure.usf computes UV coordinates for the LumBilateralGrid 3D texture using Output_ExtentInverse (1/RenderTargetSize) instead of Output_Viewport ...