Compiler Error when including InstancedSkinnedMeshComponent.h

The UE_EXPERIMENTAL macro is not used correctly in InstancedSkinnedMeshComponent.h. It should come after the 'class' keyword & before UInstancedSkinnedMeshComponent as specified in the documentation ...

Iris - HitObjectHandle not resolved when receiving FHitResult

UE - Networking - Iris - Feb 12, 2026

This seems to occur due to an interaction between how Iris handles serializing the FGameplayAbilityTargetData_SingleTargetHit struct and how the FActorInstanceHandle HitObjectHandle in the FHitResul ...

Material Parameter Collection Track doesn't work in UMG Preview from 5.7

UE - Editor - UI Systems - UMG - Feb 12, 2026

The UMG editor allows us to add a Material Parameter Control track to an animation. This track makes it possible to animate parameters used in a material. Designers can scrub the timeline and previe ...

"Move to Level" of Landscape Tool leads component scale mismatch

UE - Graphics Tools - Terrain - Landscape - Feb 12, 2026

In UE 5.7.2, when moving a Landscape Component to a sub-level using Landscape Mode > Manage > Move to Level, the proxy transform is not synchronized with the root Landscape when the KeepWorldTransfo ...

HISM causing massive spikes in BuildTreeAsync

UE - Rendering - Architecture - Feb 12, 2026

Loading a world partition cell containing dense foliage (30k+ instances per cell) causes spikes on lower end hardware of up to 10-15ms and can observe spikes of 2-5ms on high end hardware too primar ...

Attached actors have AttachmentReplication marked as dirty every net update

UE - Networking - Feb 11, 2026

In AActor::GatherCurrentMovement, bWasAttachmentModified will be set to true if the actor’s root component has an AttachParent, even if none of the values in the AttachmentReplication struct have ch ...

Division by zero causing NaN/Inf on USkeletalMeshComponent::UpdateRigidBodyScaling() when setting scale to zero and back

UE - Simulation - Core - Feb 11, 2026

Up to UE 5.5, skeletal mesh physics did not get updated when the component's scale changed. This was improved on January 2025 with CL 39190335, which addressed [Link Removed] ...

Enum Compare Condition causes crash when resetting default value of right field in State Tree's Enter Conditions

UE - AI - StateTree - Feb 11, 2026

In FStateTreeCompareEnumCondition::GetDescription, the Left.Enum value is mistakingly used when setting the RightValue. This causes crashes when resetting the default value of the Right field in an ...

StaticMesh reimport not preserving support for physical material masks

UE - Simulation - Core - Feb 10, 2026

Client has a workflow issue with the reimport pipeline: UStaticMesh::bSupportPhysicalMaterialMasks should be copied over to UBodySetup::bSupportUVsAndFaceRemap before it takes effect for raycasts, ...

FDetailGroup::AddGroup does not correctly apply the default expansion state for DetailGroups

UE - Editor - Workflow Systems - Feb 10, 2026

There is a bug affecting DetailGroups in the engine. When adding child DetailGroups to a parent DetailGroup, the expansion state does not behave as expected and ignores the flags intended to control ...