Character unnecessary step down during PHYS_Flying mode

UE - Gameplay - Player Movement - Jan 15, 2026

When MovementMode is set to PHYS_Flying, the character may unexpectedly step down by MaxStepHeight when colliding with a wall near a ceiling. This occurs because UCharacterMovementComponent::StepUp ...

"Scale for <ComponentName> has a component set to zero, which will result in a bad body instance" warning spam when moving actor instance even with Collision Profile overriden to "NoCollision"

UE - Simulation - Core - Jan 12, 2026

When a StaticMeshComponent has a scale component of zero in WorldSpace (after accumulating with the hierarchy from the root to it), function UPrimitiveComponent::OnCreatePhysicsState() logs the warn ...

A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction

UE - Simulation - Gameplay - Dec 16, 2025

Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...

Paper2D: Editor hangs when assigning Sprite Atlas Group to Sprite

UE - Gameplay - Paper2D - Dec 16, 2025

In UE 5.3 and later, assigning a Sprite Atlas Group to a UPaperSprite asset can cause the editor to hang and eventually crash. This behavior has been reproduced in 5.3, 5.6, and a recent UE5-main so ...

Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled

UE - Rendering - Architecture - RHI - Dec 3, 2025

When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...

Blueprints can enter a corrupted state where Actors construct DefaultSubobjects using CreateOptionalDefaultSubobject, even though child classes call DoNotCreateDefaultSubobject

UE - Framework - Blueprint - Nov 28, 2025

Blueprints can enter a corrupted state where Actors construct DefaultSubobjects using CreateOptionalDefaultSubobject, even though child classes call DoNotCreateDefaultSubobject. In some situations, ...

SaveGeneratedTexture2DAsset can crash when overwriting an existing asset

UE - Texture - Nov 28, 2025

SaveGeneratedTexture2DAsset can crash for a variety of reasons when overwriting an existing texture asset. When no existing asset exists, the function simply moves the provided transient Texture ass ...

same PhysicsAsset refresh multi times when modify multi SkeletalBodySetup properties in same PhysAsset

UE - Simulation - Gameplay - Nov 20, 2025

USkeletalBodySetup::PostEditChangeProperty will call OwningPhysAsset->RefreshPhysicsAssetChange(), if I modify many SkeletalBodySetup properties in same PhysAsset, will cause call OwningPhysAsset-> ...

Ensure triggered inside Range Struct Customization when Property Node is no longer valid (e.g. when editing FFloatRange while FRuntimeFloatCurve editor is visible) [Ref. UE-341339]

UE - Editor - Workflow Systems - Nov 12, 2025

[Link Removed] Closed was fixed by CL 46990575, successfully avoiding an ensure condition inside FIntervalStructCustomization::S ...

Build crash when enabling r.CreateShadersOnLoad=1

UE - Rendering - Architecture - Shaders - Nov 10, 2025

When "r.CreateShadersOnLoad" is enabled, cooking will crash due to failure to create a shader. This occurs on //UE5/Release-5.5, CL: 41545209 and //UE5/Release-5.6, CL: 45232827 ...