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 ...

Behavior Tree (BT) services added to root nodes call the initial tick twice

UE - AI - Nov 20, 2024

Behavior Tree (BT) services added to root nodes call the initial tick twice A BT Service with the setting "Call Tick on Search Start" enabled will execute the initial tick twice when added to the ro ...

FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code

UE - Niagara - Scalability - Oct 1, 2025

Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...

CitySample - Level MassCrowd - interactions with SmartObjects/ContextualAnimScene is broken in 5.5

UE - AI - Apr 9, 2025

The 5.5 version of the CitySample project, particularly the MassCrowd scene, was not properly maintained. The previously working functionality of NPCs being able to sit on a bench is now broken. CAS ...

Swapping the C++ Root Component from a Child BP class, pressing Save, Compile, but not Saving afterwards, will leave the Root Component in a locked state, meaning the it cannot be viewed or edited in the Details Panel after an Editor restart

UE - Framework - Blueprint - Dec 9, 2024

Swapping the C++ Root Component from a Child BP class, pressing Save, Compile, but not Saving afterwards, will leave the Root Component in a locked state, meaning the it cannot be viewed or edited i ...

Niagara color picker user parameter preview no longer updates until confirmation

UE - Niagara - Apr 18, 2025

Starting with UE 5.4, the Color Picker Tool no longer updates preview values in real time for certain editor windows like Niagara when working with User Parameters. This behavior is a regression fr ...

net.ReplicateCustomDeltaPropertiesInRepIndexOrder is not respect the cvar for the custom properties

UE - Networking - Nov 5, 2025

In our project do not use iris and we use a subclass UExtendAbilitySystemComponent derived from UAbilitySystemComponent. In this subclass, there is a FastArray member variable named ExtendActivatabl ...

LIVE: EDITOR: CRASH: Editor crashes on iPad4 when attempting to draw a texture that is 2048x1536

UE - Platform - Mobile - Oct 14, 2014

Build: 4.5.0-2316912 Description: .exe crashes on iPad4 when attempting to draw a 2048x1536 texture to the HUD Frequency: 2/2 Repro: [Reproduced Internally] 1. Download attached texture file. 2. Ope ...

Reversed Animations don't play properly using Skeletal Mesh Pose and animations with Keep State in Sequencer

UE - Anim - Sequencer - Nov 26, 2018

The bug seems to only reproduce when setting animations in sequencer and only if the animations are set to "Keep state". Setting them to "restore default" makes the reversed animation play correctly ...

Crash adding an AnimComposite to itself

OLD - Anim - Feb 24, 2017

Error message: Stack overflow - code c00000fd (first/second chance not available) Source Context: 74 void UAnimComposite::GetAnimationPose(FCompactPose& OutPose, FBlendedCurve& OutCurve, c ...