Crash when displaying lumencards on map with many objects

UE - Rendering - Graphics Features - Lumen - Aug 1, 2025

There is a thread conflict between FRDGBuilder execution in Background Worker and LumenVisualizer's LumenCard add/delete process. When lumen cards are displayed in a scene with many objects, a crash ...

Components added to an Actor Blueprint may not be propagated to Actors inside World-Partition Level Instances

UE - Gameplay - Blueprint - Apr 29, 2024

When a world partition level (but streaming disabled) is placed as a LevelInstance in another world partition level, actors in the inner level are cooked with an outdated component hierarchy until t ...

Sequencer Media Tracks trigger crash when an ImageSource is added

Media Framework - Jun 18, 2020

The same callstack appears in 4.24.3 (CL-11590370) but only when playing a Sequence with a Media Track that has a ImgMediaSource and Media Texture set on it. These repro steps work for 4.25 and 4.26 ...

Blueprint inheritance can cause dangling references to stale UProperties across compiles

UE - Gameplay - Blueprint Compiler - Jun 6, 2017

A number of places in the code rely on raw UProperty pointers to track properties they care about. This can present issues when BPs inherit from other BPs, because the parent's class may be Purged / ...

Dragging more than one Texture into the Material Editor causes a crash

UE - Graphics Features - Mar 11, 2020

Importing two or more Textures into the Material Editor results in a crash. This is a regression from 4.24.3 (CL-11590370) as well. This was reported and tested in 4.25 Preview 2 (CL-12055273) and ...

Crash when a subsystem calls GetSubsystemArray() on its owner while engine code is iterating on subsystems also obtained through GetSubsystemArray()

UE - Gameplay - Aug 6, 2024

In some occasions, engine code iterates over a certain subsystem type by calling FSubsystemCollection::GetSubsystemArray() and then calling some method on all subsystems of the returned array. This ...

Instance Synced properties in Blackboard cause a crash

UE - AI - May 8, 2020

Using an Instance synced property in a Blackboard causes a crash when exiting PIE. This is a regression from 4.24.3 (CL-11590370). This was reported and tested in 4.25 (CL-13144385). This was teste ...

Input consumed by a widget's action binding can be skipped if using key modifiers

UE - Gameplay - Input - Oct 29, 2021

The following code in UPlayerInput::GetChordsForKeyMapping is at fault for this:  !(KeyMapping.bAlt || KeyMapping.bCtrl || KeyMapping.bShift || KeyMapping.bCmd || ActionBinding.KeyEvent == EInputEv ...

Sliced procedural meshes do not trigger component hit events if they don't simulate physics

UE - Gameplay - Jul 14, 2016

Sliced procedural meshes do not trigger component hit events if they don't simulate physics. This seems to only occur with non-physics based hits (such a movement). When Simulation Generates Hit E ...

ContentExamples: StaticMeshes Example 1.7 "StaticMeshEditor" is all one word

Docs - Samples - Jan 19, 2017

StaticMeshes Example 1.7 "StaticMeshEditor" is all one word The word Static Mesh Editor is 3 separate words in unreal documentation https://docs.unrealengine.com/latest/INT/Engine/Content/Types/Sta ...