Unreal Engine Issues
Unreal Engine Issues
FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game
UE - Rendering - Architecture - RHI - Jan 7, 2026When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...
Morph Targets fail to reset to zero
UE - Rendering - Architecture - RHI - Jan 6, 2026"We have encountered a regression in UE 5.7 where Skeletal Mesh Morph Targets do not visually reset when all weights are set to 0.0. The mesh retains the deformation from the previous frame. This i ...
Out-of-Bounds Access During Partial Updates of ISMC Per-Instance Custom Data
UE - Graphics Features - Jan 6, 2026When using instance custom data values, removing an instance and changing the number of custom data floats in sequence can cause an array-out-of-bounds crash. The underlying arrays are not resized ...
CommonListView EntryWidgetClass allows invalid assignment via “Use Selected Asset From Content Browser”
UE - Editor - UI Systems - Jan 6, 2026CommonListView requires its EntryWidgetClass to implement UserObjectListEntry. This requirement is correctly enforced by the Entry Widget Class dropdown, which filters out widgets that only implemen ...
Skeletal Mesh BLAS updates when not animating
UE - Rendering - Architecture - RHI - Dec 19, 2025The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...
Subobject ComponentClass overrides cause failing assertions due to UObject reconstruction on AsyncLoadingThread
UE - Framework - dSTM - Dec 19, 2025Context The blueprint editor allows you to override an actor component's class in derived blueprints (component details panel -> Component Class). [Image Removed] Problem When a blueprint and it ...
Call In Editor functions not working in blueprints
UE - Editor - Developer Usability - Dec 19, 2025Context When selecting a component on an actor, any CallInEditor functions on the component's class appear as buttons in the details panel. Problem The CallInEditor functions don't execute in Blu ...
Actor Components incorrectly appearing mixed with the Scene Component Hierarchy in the Component Tab of the Blueprint Editor
UE - Framework - Blueprint Editor - Dec 19, 2025This is a regression introduced by CL 45871568 in ue5-main branch. The new function FFBlueprintEditorDefaultSortUICustomization::SortSubobjectData() in file "BlueprintEditorSCSEditorUICustomization. ...
Reflections of Masked Materials incorrect with Lumen HWRT and Max Refraction Bounces > 0
UE - Graphics Features - Lumen - Dec 18, 2025Lumen HWRT Reflections of Masked Materials are incorrect when "r.Lumen.Reflections.HardwareRayTracing.Translucent.MaxRefractionBounces" is greater than 0. The same issue occurs if the Post-Process V ...
Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor
UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...