Unreal Engine Issues and Bug Tracker

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Latest Bugs

Mass instanced skinned mesh sweep removes instances without freeing their ASTP tracks

UE - MVF Character - Animation

When an entity stops being batched into an instanced skinned mesh component, the "Collect unwanted items & remove" sweep removes its instance,...

Mutable Material Switch node not working

UE - Runtime - Mutable

When using the Material Switch node in Mutable (UE5.8), I do not seem to get pins to wire in my Materials to switch between. Other switch node...

Substrate: FPrimitiveViewRelevance::operator|= bitwise-ORs SubstrateUintPerPixel, inflating the per-pixel byte count and asserting under the blendable GBuffer

UE - Rendering - Features - Shading Models

A crash can occur due to this check in Substrate.cpp when a material with 2 units and a material with 5 (20 bpp) uints are combined triggering...

[SSAM]Textures that are still compiling are all counted as UnknownRef

UE - World Creation - Worldbuilding Tools

In UE5.8, the texture scale fallback is no longer applied when SSAM is enabled. As a result, if a material cannot access its TextureStreamingD...

FDebug::EnsureFailed will only broadcast OnHandleSystemEnsure 4 times.

UE - Core - Systems

A licensee is reporting that OnHandleSystemEnsure will only be broadcasted for the first 4 ensures in the life of the process. This is hardcod...

Latest Fixes

Uploading of the SBT via copy queue is not guaranteed to be synced with async compute queue but only direct queue in d3d12

UE - Rendering - Features - Ray Tracing

When HitLighting is enabled, SBT commit is running on the Graphic Queue, and the pass "LumenSceneLighting->offscreenshadows->LumenDirectLighti...

GameplayTagEventMap is cleared on clients when "AbilitySystem.Fix.ReplicateTagCountContainerWithIris" is enabled

UE - Gameplay - Gameplay Ability System

FGameplayTagCountContainer::Reset() leaves explicit tag state and causes counts to accumulate

UE - Gameplay - Gameplay Tags

[Summary] In UE 5.7 and later, if a tag is added once to an FGameplayTagCountContainer, the container is reset, and the same tag is added onc...

In 5.6, bWarningsAsErrors does not work with clang

UE - Core - Cpp Tools - UnrealBuildTool

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes: [WarningsClangToolChain...

Preview rendering does not update when slider is moved below 0.0 in timeline on in Niagara Editor.

UE - Rendering - Architecture - Niagara

Workaround in UE5.3: UNiagaraComponent::TickComponent if (AgeDiff < 0.0f) { SystemInstanceContr...