Unreal Engine Issues
Unreal Engine Issues
Lumen HWRT "hit lighting" doesn't respect lighting channels
UE - Graphics Features - Lumen - Dec 10, 2025Lumen hardware raytracing "hit lighting" doesn't respect lighting channels. See the provided repro project. Perhaps in 5.5.x, RT simply ignored non-channel-zero lights, but we didn't notice it prev ...
[ALT] - UE56 Editor launched with -AsyncLoadingThread will trigger MTAccess
UE - DEET - EditorLoader - Dec 10, 2025When launching the editor with the -AsyncLoadingThread command, the engine uses an asynchronous thread to load and instantiate UObjects. At this point, if the instantiated UObject contains an FData ...
Convex hull generation fails when first 3 verts are colinear
UE - Simulation - Core - Dec 9, 2025The licensee identified a number of cases where loading assets will trigger convex hull generation warnings:If the first 3 verts in the set are colinear (in which case IsPlanarShape() returns true b ...
Texture Streaming can randomly streams in all Mips, causing large memory spikes
UE - Graphics Features - Dec 5, 2025A possible race condition allows texture instance views to read uninitialized bounds, causing either garbage or zero screen size values to be returned by FRenderAssetInstanceAsyncView::GetRenderAsse ...
Drag and Drop fails in Standalone and Packaged builds when WidgetComponent’s Widget is set at runtime
UE - Editor - UI Systems - Dec 4, 2025When a UWidgetComponent has its widget assigned dynamically at runtime using CreateWidget and SetWidget, drag & drop operations fail in Standalone Game and packaged/game builds, while working correc ...
Morph target is not applied on the first frame in Level Sequence
UE - Anim - Runtime - Dec 4, 2025When a skeletal mesh with morph targets spawns in the sequence, the morph is not reflected in the first frame. In the ProcessStage_SkinCache call of SkeletalMesh, MorphVertexBuffer->SectionIds is ...
Mover plugin: Crash on UFloorQueryUtils::ComputeFloorDist() and other utility functions that assume the pawn uses a UCapsuleComponent
UE - Gameplay - Player Movement - Mover - Dec 4, 2025The following functions have been found to perform unchecked casts of the pawn's "UpdatedComponent" to class UCapsuleComponent, possibly resulting in crashes:UFloorQueryUtils::ComputeFloorDist()UGro ...
UInstancedStaticMeshComponent::AddInstances does not appear to be adding per-instance previous transforms when enabled
UE - Graphics Features - Dec 3, 2025Instanced static mesh component does not add instances transforms to PerInstancePrevTransform array when using UInstancedStaticMeshComponent::AddInstances. Additionally Updating the transforms of th ...
Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled
UE - Rendering Architecture - RHI - Dec 3, 2025When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...
Pass names appear as "RDGEvent" in Unreal Insights when r.rhisetgpucaptureoptions=1
UE - Rendering Architecture - RHI - Dec 2, 2025When capturing a trace in Unreal Insights, all r.rhisetgpucaptureoptions=1 (r.RDG.Events=3) all RDG pass events appear simply as RDGEvent, without the actual name due to the logic for RDG_EVENT_SCOP ...