Child Actor components on Clients use the incorrect default values for variables that are not being replicated

UE - Gameplay - Blueprint - Aug 28, 2018

When a Child Actor's class is replicated but the individual variables are not, the individual variables will use the default of the original BP class instead of the defaults that were set in the Chi ...

Missing Service Node warning when opening project

UE - AI - Sep 24, 2018

Services in the Behavior Tree sometimes don't work when the project is first loaded. The Behavior Tree will print a "missing service node" warning and the BT will remain inactive. This was reported ...

Skeletal Mesh rigid body simulation is not being updated with correct bones locations right after Skeletal Mesh is spawned

UE - Simulation - Physics - Nov 5, 2018

When simulating in Editor, the Skeletal Mesh bone locations are not being passed into simulate if the simulation is being toggled the same frame when the Mesh is being set on a Skeletal Mesh compone ...

Confusing build error message provided when semi-colon is not added after a forward declaration in an Interface header file

UE - Foundation - Cpp Tools - UnrealHeaderTool - Feb 15, 2019

If a forward declaration of a class is made in the header file for an Interface class, and no semi-colon is included at the end of the forward declaration line, the build will fail with a confusing ...

Creating Online Session always fails in Launch mode when loading another map

UE - Networking - Aug 5, 2019

Creating an Online Session and transitioning to another map does not work in a Launched Windows game. The transition event does fire but it just resets the players position on the Default map. This ...

ARKit: Metal Desktop Renderer + Metal v2.1 = Black View

UE - Platform - XR - Jan 26, 2020

If Metal Desktop Renderer and Metal v2.1 are both active, the AR passthrough camera renders as black. Issue not observed if only 'Metal Desktop Renderer' or 'Metal 2.1' is selected Issue not obs ...

Landscape Grass does not spawn initially outside Foliage Mode

UE - World Creation - Worldbuilding Tools - Foliage - Mar 26, 2020

Foliage spawned from Landscape Materials is not initially created. The user must enter Foliage Mode before the refresh is pushed and foliage is created. I can reproduce this issue with or without E ...

Nvidia Graphics Drivers cause editor menus to flicker and disappear after using the editor for an extended period of time

UE - Graphics Features - Apr 16, 2021

This issue seems to be occurring on a variety of Nvidia cards. So far, I haven't seen any indication that it is affecting AMD graphics cards. The majority of the reports have indicating that the pro ...

Editor 'Build All Levels' discards Volumetrics Lightmaps in persistent level

UE - Graphics Features - May 14, 2025

Building the level or lightmaps can clear the volumetric lightmap. In 5.5, this requires you to perform a full build, or a lighting only build with a BSP brush in the scene. In 5.6, all level build ...

Static code functions cause associated blueprints to not compile after a hot reload

UE - Foundation - Cpp Tools - Hot Reload - Oct 14, 2016

If a function inside a BlueprintFunctionLibrary class is declared as static, instances of the function node inside blueprints cause the blueprint to not save after a hot reload. This does not affec ...