Adding OnClicked to SButton in Editor Mode plugin crashes editor when accessing the plugin

UE - Foundation - Cpp Tools - Plugin System - Mar 16, 2016

If a new editor plugin has a button added with OnClicked functionality, the editor will crash immediately when accessing the plugin. Removing the OnClicked portion of code allows the plugin to be a ...

NPC - Does not get updates from Material Parameter Collection changes in the editor

UE - Niagara - Sep 30, 2024

When an MPC is selected as the Source Material Collection for an NPC, all of its current parameters are carried over to the NPC with their current values. After that, if parameters are added to, rem ...

Rigidbody world space simulation overwrites scaling of the skeletal mesh

UE - Simulation - Physics - Character - Nov 14, 2022

Reproduced 3/3 times. Issue also occurs in //UE5/Release-5.0 - CL 20979098 Binary. Not a Regression. ...

Crashes when attempting to use an Instanced Struct inside Control Rig / Rig VM

UE - Anim - Rigging - Control Rig - Mar 17, 2025

Currently, the Control Rig Editor allows the user to use the "Instanced Struct" type, for example for a variable or function input/output. However, this type does not seem to be properly supported ( ...

(GAS) Block tags are ignored in version 5.5.2 if two abilities share the same parent tags structure.

UE - Gameplay - Gameplay Ability System - Feb 5, 2025

Block tags are not working correctly in version 5.5.2, it was working in 5.5.1. This is caused by a change done in version 5.5.2. The exact CL is: CL 35930696 ...

Blueprint derived from C++ class not saving correctly

UE - Gameplay - Blueprint - Jul 27, 2015

The blueprint that the user is using loses some data when the editor closes and reopens despite saving all of the content. Note: Currently unsure of what exactly causes this but as I am able to rep ...

Unreal Header Tool can sometimes fail if an Engine plugin is Enabled By Default and has the "Program" Module Type set

UE - Foundation - Core - Feb 15, 2018

An Engine plugin with the Program module type and EnabledByDefault set to true can cause the Engine to fail to build successfully due to UHT failing. I was only able to reproduce this behavior using ...

GeneratePsyms fails with installed builds due to missing dymp_syms tool and incorrect path space handling

UE - Platform - Apple - Nov 14, 2024

Uncovered while testing [Link Removed] ...

Inaccurate motion vectors when using different position binding in renderer

UE - Niagara - Rendering - Jul 27, 2023

Even though the particles are not moving, and the velocity is zero, the output motion vectors are non-zero. This seems to only happen if using two sources of particle positions.  ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...