Loading a blueprint with an invalid gameplay tag container pin causes ensure and data loss

UE - Gameplay - Feb 23, 2021

The gameplay tag system depends on tags being registered with the global manager as valid in order to correctly read them off disk. Two different issues are combining to cause a confusing ensure and ...

Chaos : Rigid body sleeps when very small external force is applied by AddForce

UE - Simulation - Physics - Solver - May 25, 2022

When a small external force is applied to the rigid body, the VSmooth value is reset in the ResetVSmoothFromForces function. Since this function ignores the current velocity, a very small velocity ...

Widgets will bind input delegates to the Player Controller's Input Component, but never unbind them

UE - Editor - UI Systems - UMG - Jan 30, 2024

This is a bug introduced with 18468289 a while ago. We added this functionality for [Link Removed], which allows input event nodes to be placed within widgets and have them behave correctly.  This ...

Typo in GetAsBoundsArray() from file AABBTree.h on Chaos module

UE - Simulation - Core - Jul 30, 2025

From file [Engine\Source\Runtime\Experimental\Chaos\Public\Chaos\AABBTree.h], function Chaos::TAABBTree<>::GetAsBoundsArray(): bool GetAsBoundsArray(TArray<TAABB<T, 3>>& AllBounds, int32 NodeIdx, i ...

EDITOR: LIVE: CRASH: Reroute nodes can cause a loop that freezes the editor.

UE - Gameplay - Blueprint - Jul 29, 2014

Branch Build Label UE4-Main Promoted-CL-2230001 DESCRIPTION: If reroute nodes are used to make a loop, the editor will not catch it and the loop will freeze the editor. ADDITIONAL NOTES: Creatin ...

Setting a struct bool property (bitfield) to itself writes the wrong value

UE - Framework - Blueprint Compiler - Sep 17, 2025

There's an issue when assigning a bitfield bool to a native bool in Blueprints. Currently, the engine erroneously treats the memory for a local bool as a uint8 bitfield, which is undefined behavior. ...

Some materials render black on Iphone 6 series phones

UE - Platform - Mobile - Oct 6, 2016

Some materials are not rendering on iphone 6 series devices. They will render completely black on one device but not others in the same series. Replacing the material with a basic material renders o ...

[CrashReport] UE4Editor_Engine!FPointerToUberGraphFrame::~FPointerToUberGraphFrame()

UE - Gameplay - Blueprint - Aug 15, 2017

This is a trending crash coming out of the 4.17.0 release. Users have not provided any descriptions of their actions when the crash occurred, however the callstack is very similar to [Link Removed] ...

[CrashReport] UE4Editor_Landscape!FLandscapeComponentSceneProxy::FLandscapeComponentSceneProxy() [landscaperender.cpp:680]

UE - LD & Modeling - Terrain - Landscape - Apr 11, 2018

User comment in crash group:Wanted to delete a single field of my landscape wich is very big. Same error appears if I try to get a part of the landscape to another streaming level. Would be cool if ...

Undo/Redo can cause the gizmo to desync from a leaf-selected component

UE - Editor - Workflow Systems - Oct 18, 2021

This is a regression from 4.27. This is happening because of the change to typed elements. UEditorEngine::PostUndo, when combined with the typed element changes causes the selection set to reorder ...