Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script

UE - AI - Oct 8, 2025

An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...

TargetArray nodes are reported as invalid if played in Standalone mode but not in PIE

UE - Gameplay - Blueprint - Feb 20, 2015

TargetArray nodes are reported as invalid if played in Standalone mode and the blueprints they are contained in are not rendered. Playing in PIE however works correctly and all blueprints are rende ...

Enabling bUpdateComponentTransformToRootBone in a GeometryCollectionComponent causes broken particles to appear in the wrong location

UE - Simulation - Visual - Jun 22, 2025

Enabling bUpdateComponentTransformToRootBone in a GeometryCollectionComponent causes broken particles to appear in the wrong location. When that flag is true, the moment the GeometryCollection (GC) ...

Steam Overlay does not show in Win64 Shipping builds when run outside of Steam

UE - Networking - Nov 11, 2015

Steam Overlay does not show in Win64 Shipping builds when run outside of Steam. The Steam client can be running, but unless the .exe is opened through Steam itself, the Overlay will not appear. Note ...

Import then cancel while file is read leads to potential crash

TM - Interoperability - Oct 6, 2025

1/ Import a file with mootools such as an fbx 2/ while the file is still read, cancel the import Result : may crash few times after (when theoretically the file has finished being read) - not repr ...

Component in Child Blueprint Parented to Inherited Component Disappears

UE - Gameplay - Components - Mar 4, 2016

When you have a child blueprint that contains a component that is parented to an inherited component, changing a value on that inherited component in the original parent blueprint and then compiling ...

Navigation does not work in sub-levels

UE - AI - Jan 28, 2015

Navigation does not work in sub-levels. If the Nav Mesh Bounds Volume in a sub level is not touching a Nav Mesh Bounds Volume in the Persistent Level, it will not appear or function during Play. It ...

Does Container Match Tag Query Node doesn't find existing Gameplay Tags in Packaged Project with Nativized Blueprints

UE - Gameplay - Aug 26, 2019

When using the "Does Container Match Tag Query" node doesn't return true when a gameplay container member has the searched for gameplay tag in a blueprint that has been nativized. Packaging in Excl ...

Light function does not work with volumetric fog when not compatible with light atlas

UE - Graphics Features - Mar 28, 2025

Light functions do not work as intended with volumetric fog when using clamped mask textures which are not compatible with the light function atlas. In light functions materials, when using any UV ...

[CrashReport][Assert] UnrealEditor-RHI!FRHIResource::MarkForDelete() [Engine/Source/Runtime/RHI/Private/RHIResources.cpp:49]

UE - Rendering Architecture - Materials - Dec 18, 2024

One of the users described this issue as below. "At seemingly random times while working in the material graph, some action will cause a hitch or freeze, and quickly after the engine will crash, an ...