Mutable compile hangs indefinitely when using Customizable Object Extension Data Constants

UE - Anim - Mutable - Oct 25, 2025

I am getting a CO compile to hang indefinitely while compiling. It seems to be caused by the optimization in LocalLogicOptimiserAST that tries to convert 3+ conditionals into a switch statement. It ...

SetGamePause does not affect Sequencer pause if using audio clock as source

UE - Audio - Sequencer - Oct 24, 2025

We’ve run into some unexpected behavior when combining SetGamePause(true) with Level Sequences. When calling SetGamePause(true) while a Level Sequence is playing, the visuals pause correctly, b ...

bStaticWhenNotMoveable in Lighting category instead of Physics

UE - Simulation - Gameplay - Oct 24, 2025

"UPrimitiveComponent::bStaticWhenNotMoveable"'s category is set to Lighting, not Physics. This causes it to be hidden when lighting-related properties are hidden, even though it controls physics sta ...

Variant Manager: LevelVariantSets asset corruption after rename or duplicate

UE - Editor - Content Pipeline - Oct 24, 2025

When renaming or duplicating a LevelVariantSets asset that contains a Director Blueprint, the internal DirectorClass reference becomes mismatched. Although the DirectorBlueprint pointer updates corr ...

Missing materials on the rear lights and windows of library vehicles

TM - Content - Oct 24, 2025

Reported in SF [Link Removed] The rear light material and window materials on Twinmotion library vehicles are not present on many vehicles in TM 2025.2. Confirmed affected vehicles are in the foll ...

VulkanStagingBuffers stat continually to grows.

UE - Platform - Mobile - Oct 24, 2025

On Android phones, VulkanStagingBuffers continually grows when the scene is static. From looking at FStagingManager, it appears the VulkanStagingBuffers atat is only updated on buffer acquisition, ...

“None” option removed from “Preview Game Language” in Editor Preferences since UE 5.6

UE - Editor - UI Systems - Oct 24, 2025

In Unreal Engine 5.5 and earlier, users could select “None” as the Preview Game Language in the Editor Preferences. Starting from UE 5.6, this “None” option is no longer available. Based on source ...

Lumen reflections break when the normals don't match the pixel depth information.

UE - Graphics Features - Lumen - Oct 23, 2025

Lumen Reflections can leave black spots in chrome materials with strong normals. Also tested on UE 5.5, CL: 41545209 and UE 5.6, CL: 45232827 ...

CLI: Exporting COLMAP with selected mask layer doesn't export the masks.

RS - Alignment - Oct 23, 2025

When using the -exportRegistration command with an XMP parameters file, where the mask layer is selected for export, geometry images are exported instead. The mask export is successful from the use ...

Swarm Agent Binaries Missing in Launcher 5.7 Preview

UE - Foundation - Build - Rocket (Installed Engine) - Oct 23, 2025

The Swarm binaries are missing from Engine\Binaries\DotNET in the 5.7 Preview launcher version of the engine. This causes any lighting build or precomputed static visibility builds to fails due to t ...