Crash undoing "replace actor with" when replaced object constructs child actors

UE - Gameplay - Oct 10, 2016

The problem seems to be that the construction scripts doubled up all the BlueprintCreatedComponents, so there are now 2 scene components(actually the same one duplicated) and now 2 child actor compo ...

Niagara Crash After Adding More Than 20 Emitters to a System

UE - Niagara - May 24, 2019

The Editor will crash after adding more than 20 Emitters to a system. Found in 4.20 CL# 4369336, 4.21 CL# 4753647, 4.22 CL# 6574378, 4.23 CL# 6599617 ...

Unable to import animation data from fbx with bone names starting with a number

UE - Anim - Rigging - Control Rig - Jul 31, 2023

When importing animations with numeric names from fbx in UE5.2 or later, the AnimationSequence asset is created but the animation data is not imported. The workaround is to not prefix bones with num ...

Android + Bluetooth Mouse: Hover events and Get Mouse Position on Viewport not working

UE - Platform - Mobile - Jul 11, 2018

No hover events firing when using a bluetooth mouse on android. Tested with 4.20p5 CL# 4173645 4.21 CL# 4179794 ...

CSM Shadows disappearing at larger coordinates with different FOVs

UE - Graphics Features - Shadows - Apr 5, 2024

Cascaded shadows disappear at some FOVs when far from the world origin. This behavior was not present in 5.2. Also found in CL: 32690246 in Release-5.4 ...

Interaction between sublevels and LevelSequences can break actors attachments hierarchy of the sublevel.

UE - World Creation - Worldbuilding Tools - Aug 6, 2025

Having a LevelSequence opened and unhiding a sublevel can break the attachment hierarchy of the actors that are inside the sublevel. This also affects to the sublevel asset itself. ...

[Interchange][FBX] Import of custom collision add the collision mesh material slot to the mesh material slot

UE - Editor - Content Pipeline - FBX - Jan 20, 2025

cf part 2 of that UDN https://udn.unrealengine.com/s/question/0D5QP00000rP4CG0A0/interchange-custom-collision-changes-from-fbx-pipeline?fromCase=1 ...

Using the Set Position in Viewport changes anchor values to 0

UE - Editor - UI Systems - Dec 15, 2017

When Using the "Set Position in Viewport" it changes anchor values of a widget to 0. This node seems like this should not be changing the anchor values, but it is unsure if this is intended behavior ...

USD Stage Import - Spawned actors by USD importer are not saved in level

UE - Editor - Content Pipeline - USD - Jul 20, 2023

we ran into an issue with USD Importer plugin for Unreal 5.2. When you import a USDStage with the "actors" import option - which respawns the newly imported actors into the current level.  However, ...

UnrealMatch3 ensures when launching on iOS

Docs - Samples - Aug 21, 2016

While running regression pass, found that UnrealMatch3 hits an ensure when user selects to Launch on to iOS device. LogOutputDevice:Error: The ini file '../../../UnrealMatch3/Saved/Config/IOS/Device ...