Unreal Engine Issues
Unreal Engine Issues
Visibility track key value is no longer the inversion of the bound bHidden property
UE - Anim - Sequencer - May 13, 2026Regression introduced in UE 5.7. Works correctly in UE 5.6. Up to UE 5.6, the bool value written to the Visibility track's BoolCurve was the inversion of the underlying bound property (e.g. AActor: ...
Resavepackages commandlet strips level package thumbnails
UE - Editor - Developer Usability - May 12, 2026When loading thumbnails in FLinkerLoad::SerializeThumbnails, the level asset has two thumbnails. The first one has a size of 0, which causes the loading process to abort early. Since the actual thum ...
Material parameters flickering due to UMG animation switching and multi-threaded execution
UE - Editor - UI Systems - UMG - May 12, 2026When continuously transitioning to UMG animations that have a track targeting the same material parameter within the UUserWidget::OnAnimationFinished event, the number of source inputs to UMovieScen ...
Replication Graph - Reliable multicast RPC may be dropped for actor recently set to dormant
UE - Networking - May 8, 2026The replication graph will wait until the client acks the close bunch and the actor channel is cleaned up to remove the channel from the ActorInfoMap (see UNetReplicationGraphConnection::NotifyActor ...
Chaos FieldSystem examples in the engine content add field nodes every Tick, which creates too many components
UE - Simulation - Gameplay - May 5, 2026Can we add the field on construction instead of on Tick to avoid the performance overhead caused by creating too many components? ...
Level Instance Property Override: Actor::Tags overridden pre-CS but clobbered by RerunConstructionScripts with no post-CS re-apply
UE - World Creation - Worldbuilding Tools - May 4, 2026Summary When using the Level Instance Property Override system, overrides applied to `AActor::Tags` are silently lost for Blueprint actors whose Construction Script assigns or appends to `Tags`. The ...
Curve Atlas Row Parameter uses derivative ops when Texture Sample connected to curveTime input
UE - Rendering - Architecture - Materials - May 1, 2026When a Curve Atlas Row Parameter node is used with a Texture Sampler connected to the curve time input, the sample type uses derivative ops. This has negative performance implications for Nanite co ...
Blueprints: ComponentClass override causes crash on loading maps with instances saved with base class
UE - Framework - Blueprint - May 1, 2026Context In actor blueprints, you can change an inherited component’s class in the editor by selecting it in a child blueprint and changing its Component Class in the Details panel. Problem When o ...
Crash in FNiagaraEditorModule::PrecompileDuplicate() — null deref of Handle.GetEmitterData() in third "finish off the emitters" loop
UE - Niagara - Apr 30, 2026Crash / null pointer dereference in FNiagaraEditorModule::PrecompileDuplicate(). File: Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Private/NiagaraCompiler.cpp Function: FNiagaraEditorModule::Pre ...
Open Formats: Interchange Import Runtime - Interchange ImportAssetAsync runtime GLB import — materials, textures, tangents, and shaders non-functional in packaged builds (6 issues, UE 5.7.4)
UE - Editor - Open File Formats - Apr 30, 2026Description* We are using Interchange's `UInterchangeManager::ImportAssetAsync()` to import GLB files at runtime in a packaged (Shipping) application. The orchestration layer (`ImportInternal` in `In ...