Unreal Engine Issues
Unreal Engine Issues
MovieSceneAnimMixer: Force Root Lock suppression is editor-only, causing PIE vs cooked divergence
UE - Anim - Sequencer - Jul 13, 2026The anim mixer's skeletal animation eval task suppresses an anim sequence's Force Root Lock during pose evaluation so the root-motion extraction task (FAnimNextExtractRootMotionTask) can measure and ...
Open Formats: Interchange Import - UCX Convex Hull Import Bug
UE - Editor - Open File Formats - May 25, 2026When importing custom UCX collision meshes from FBX files into Unreal Engine, certain geometry profiles fail to generate correctly if the option "One Convex Hull Per UCX" is unchecked. The engine's ...
Cluster Group Index Causes Incorrect Break Events in Geometry Collections
UE - Runtime - Deformable - Feb 25, 2026More details in this [Link Removed] ...
Incorrect geometry for OnMouseMove event on Slider with RightToLeft flow direction
UE - Editor - UI Systems - Slate - Jan 28, 2026When a slider is in RTL flow direction, and thus its position is changed, the handle is not drawn at the correct position during mouse drag. Instead, the handle draws as if the slider was not moved ...
Controller Mapping/Unmapping on some platforms is not ideal for local multiplayer
UE - Gameplay - Input - Nov 19, 2025[Link Removed] The workaround is as I posted in the UDN, to override the viewport client or to make a custom slate input mapping to change this behavior. But, there is a bug with that unmapping/l ...
ChordBlockers don't work as expected when ChordAction is set in InputAction
UE - Gameplay - Input - Jun 3, 2025In the Enhanced Input System, when using a UInputTriggerChordAction to define a chorded input (e.g., Shift + W), the automatic chord blocking system (UInputTriggerChordBlocker) only functions correc ...
CheckCompilingPSOs assert in FMaterialPSORequestManager::MarkCompilationComplete fires occasionally
UE - Rendering - RHI - May 17, 2025Find the root cause and fix it. Potential issue based on logs:New RequestA is created in PrecachePSOs and its collection task is dispatched and finishedRequestA is waiting for compilation taskReque ...
Fields with Maximum resolution are not affecting all leaves of a Geometry Collection
UE - Runtime - Deformable - Apr 25, 2025Fields with Maximum resolution are not affecting all leaves of a Geometry Collection on 5.4 and onwards. When calling GetRelevantParticleHandles() a Maximum Resolution field does return all particl ...
Add support for motion data on SteamDeck (Steam Controller plugin)
UE - Gameplay - Input - Mar 7, 2025We have a UDN user with a proposed change: https://udn.unrealengine.com/s/question/0D5QP00000yo70w0AA/add-support-for-gyro-motion-data-to-steam-controller-plugin?fromCase=1 Hi, we were adding gyr ...
Enhanced input user settings file on consoles may behave unexpectedly after login change
UE - Gameplay - Input - Feb 27, 2025The user settings seem to be initialized incorrectly. I think that this might be because, technically, when you log out and sign back in we might use the same ULocalPlayer in some cases on the conso ...