Unreal Engine Issues

Chaos Cloth - Visualization materials cause async load flush and slows down starting a PIE session.

The loading of the cloth visualization materials disturbs async loads shortly after starting PIE which causes an async flush and several seconds stall. The solution would be to move these to a sing ...

Tracks that manipulate byte properties may have different (non-deterministic) results even for the same frame

This issue is relatively easy to reproduce, e.g., in the timing of switching between the two types of property operations within the same track. It seems to be easy to reproduce the above problem in ...

Sequencer- 'Dynamic Binding' SoftObjectPtr parameters fail to resolve after reloading editor

When reloading the editor and a level where a sequence has a dynamic binding with a soft object ptr parameter to an actor in the same level, the director blueprint will recompile on load of the leve ...

Volumetric cloud shadow bug with two directional lights

Crash in FPBDJointUtilities::ConditionInverseMassAndInertia

We seem to be setting the InverseInertia to zero, even though the InverseMass is non-zero. FPBDJointUtilities::ConditionInverseMassAndInertia assumes that the inverse inertia is only zero if the in ...

Motion Matching: Check failure when adding sequence into DB that references a niagara emitter

The serialization code for the motion matching database has a check that will fail if a property has the IgnoreForMemberInitializationTestName meta tag.  Niagara emitters contain a property that has ...

USplineMeshComponent::CalcBounds may return invalid value

USplineMeshComponent::CalcBounds function should be returning an FBoxSphereBounds type, but in the implementation it instead outputs an FBox. This may result in the returning of invalid results, esp ...

Material base color is lighter on Nanite meshes when using 16-bit GBuffer

The base color is brighter on Nanite meshes than non-Nanite meshes when GBuffer Format is set to "Force 16-bits per channel" (r.GBufferFormat 5) even though the meshes are using the same material. ...

Screen Probes and Specular Firefly Flickering near screen edges

Lumen's rough specular indirect lighting buffer can have fireflies along the bottom and right edges of the screen. Also tested in //UE5/Main, CL: 35177423 ...

Streaming level is not visible when WorldPartitionRuntimeHashSet level is preloading and transitioning with package game.

In levels where "WorldPartitionRuntimeHashSet" is specified as the runtime hash class, the world partition may not be correctly visible only in the package. This issue is reproduced only in packaged ...