Unreal Engine Issues
Unreal Engine Issues
Crash in GC - FSharedStruct reachability race condition
UE - CoreTech - Jul 13, 2026This Jira was created from the linked EPS case: =============================================== This issue is caused by FSharedStruct batching reachability requests to the same underlying FInstan ...
Parameter metadata not accessible if modified in Material Instance and then converted to CustomPrimitiveData
UE - Rendering - Architecture - Materials - Jun 24, 2026There’s a potential issue with some changes we made to UMaterialInstance::GetParameterValue (https://github.com/EpicGames/UnrealEngine/commit/8f2bebb008ba645f5938da844cd46b0925322b13). It seems as t ...
Rare crash in FWidgetAnimationState::OnStopped
UE - Anim - Sequencer - Jun 22, 2026The FWidgetAnimationState::OnStopped delegate is getting created when the widget anim state is being destroyed and then queued to be executed later. Something is happening between the queue and the ...
[StateTree] StateTree fails to transition to the next state in child states when parent state contains some tasks
UE - AI - StateTree - Jun 12, 2026StateTree fails to transition to the next child state in a tree where the parent state has a task such as Debug Text which does not influence state completion. The ST atttempts to transition from Le ...
Custom Items and Inventory can appear enabled while actually being disabled
UE - Gameplay Features - Itemization - Jun 10, 2026Toggling the Custom Items and Inventory setting and then closing the editor without saving can lead to a mismatch between the Project Settings Custom Items feature and the IslandSettings object in t ...
Sequencer - if you set the Take Separator to - rather than _ the New Take naming will mess up
UE - Anim - Sequencer - Jun 9, 2026When using a non-default take separator (eg "-") the "New Take" option produces a malformed proposed name for the take. ...
Nanite: unused VertexInterpolator node disables Opacity Mask (material renders opaque)
UE - Rendering - Architecture - Jun 8, 2026On Nanite meshes, placing a VertexInterpolator node in a material graph without using it (unconnected, or routed through a disabled static switch) silently breaks the Opacity Mask and the material r ...
Mutable Dataless Generation - Regenerate Imported Models Crash
UE - Anim - Mutable - Jun 8, 2026Crash when working with Dataless Mutable content. When selecting meshes in the instance, there is a crash in RegenerateImportedModels. ...
Niagara NDC GPU Instance Counter leak
UE - Niagara - Jun 5, 2026In NiagaraDataChannelData.cpp, FNiagaraDataChannelDataProxy::EndFrame enqueues a GPU readback for each entry in PendingGPUReadbackBuffers, but the corresponding FNiagaraGPUInstanceCountManager::Free ...
UBackgroundBlur crashes at PSO creation under D3D12 SM6 when stereo rendering is enabled
UE - Editor - UI Systems - Slate - Jun 4, 2026Any Slate widget that triggers the Slate post-process blur (e.g., a UBackgroundBlur with non-zero strength) hits a fatal D3D12 CreateGraphicsPipelineState failure on first render. The fatal is funne ...