Unreal Engine Issues
Unreal Engine Issues
[Enhanced Input] Chord trigger fails when its referenced action lives in a lower-priority IMC
UE - Gameplay - Input - May 18, 2026Summary A UInputTriggerChordAction does not fire when the action it references (the "chording action") is mapped in a different Input Mapping Context with a lower priority than the IMC containing the ...
check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process
UE - Rendering - Architecture - RHI - May 18, 2026FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...
Meshes with scaled root bones pop when entering simulation
UE - Simulation - Core - May 15, 2026This issue is fallout from the changes in 33851494. Prior to that, we didn’t get the pop on beginning the sim. The problem appears to be that in USkeletalMeshComponent::PerformBlendPhysicsBones we ...
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 ...
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? ...
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 ...