Unreal Engine Issues
Unreal Engine Issues
Translucent materials in the PostMotionBlur pass can cause a flickering viewport artefact when using TAA
UE - Rendering - Graphics Features - Feb 5, 2025There appears to be a bug relating to rendering multiple windows that can trigger under unknown circumstances. It has been reported on rectangle lights in the forums and on PostMotionBlur materials ...
Blueprint improperly marked dirty when it contains a latent node with a byte enum
UE - Framework - Blueprint Editor - Sep 23, 2024In UE 5.4, when deleting actors in our levels, some blueprints will be mark dirty despite not having changed. We traced that down to FAssetRenameManager::CheckPackageForSoftObjectReferences. The af ...
Incorrect config property serialization for UStructs used as TMap keys or contained in a TSet with a single value. Diffs taken from default-value of each member type, instead of from default-value of the struct
UE - Core - Systems - Nov 18, 2024Consider a UStruct with some basic type members, each one with a default value specified in the struct. Also consider a TSet or TMap with that struct as keys, used inside a UObject as a UProperty an ...
Enhanced Input Gesture keys (Pinch/Rotate/Flick) never release after touch ends — regression in 5.8
UE - Gameplay - Input - Aug 20, 2026POST LINK: https://forums.unrealengine.com/t/enhanced-input-gesture-keys-pinch-rotate-flick-never-release-after-touch-ends-regression-in-5-8/2745006 POST BODY:Summary An Input Action mapped directl ...
Wrong density calculation in UBodySetup::CalculateMass
UE - Runtime - Simulation - Sep 29, 2025Wrong density calculation in UBodySetup::CalculateMass. The licensee has provided the following analysis and suggested fix: In UBodySetup::CalculateMass, the following code is present: // physical ...
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 ...
Regression: Several project settings, especially from built-in Plugins, are being silently erased when previously they were not, which is perceived as a bug
UE - Core - Systems - Feb 28, 2025In UE's Project Settings, some pages are saved automatically to the project's "Config/Default<CATEGORY>.ini" file (meant to be version-controlled) on every change. Other pages have buttons "Set as D ...
Chaos: geometry collection with One Way Interaction never breaks from its own collisions
UE - Runtime - Simulation - Aug 21, 2026A geometry collection with One Way Interaction Level set to 0 never breaks from its own collisions. It falls, lands, and stays intact no matter what it hits. Set the level to -1 (feature off) and ch ...
Camera behavior during "Orbit Pan Mode" (Alt+MMB+Drag) is wrong while piloting an actor
UE - Editor - Nov 18, 2025In the Level Editor, dragging the mouse while the "Alt" key is pressed performs one of the "Orbit" movements: OrbitRotation, OrbitPan, OrbitZoom. The same can be done while Piloting an actor. Howev ...
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 ...