If a function that takes a custom struct as a parameter is changed and a hot reload performed, any variables in Blueprints that are of that custom struct type will disappear and no longer be usable.

UE - Gameplay - Blueprint - Aug 27, 2015

After creating a custom struct in C++ and adding a variable of that struct type to a Blueprint, hot reloading a code change that involves altering a function that takes the struct as a parameter res ...

Failed Import for Spline Component Error Appears on Restarting Level

UE - Gameplay - Blueprint - Jul 5, 2016

When creating and declaring a Spline Component in code, placing an instance of a blueprint derived from that class in the level causes a failed import message to appear upon restarting the level. ...

Packaged Project with Media Player Asset 'From Memory' Crashes and Corrupts Project

Tools - Feb 9, 2015

There is no Callstack associated with this crash. And I was unable to reproduce this in main due to a known issue when switching the 'Stream Mode' to 'From Memory'. When packaging a project in 4.6. ...

AddChildActorComponent in Construction Script Causes Pending Kill Error

UE - Gameplay - Blueprint - Feb 16, 2016

When using AddChildActorComponent in the construction script of an actor and attempting to get a reference to the child actor that is stored in a variable on Event Begin Play, the editor throws erro ...

Details panel for Actor Component is blank in any Blueprint that derives from a code class using that Actor Component after the Actor Component's class name is changed

UE - Gameplay - Blueprint - Dec 20, 2018

Changing the name of an Actor Component code class in a project results in any existing Blueprints that derive from code classes that use that Actor Component to not display the Actor Component's pr ...

Creating a function with parameter type TEnumAsByte<MyEnum> will crash while compiling

UE - Editor - Workflow Systems - Jan 11, 2022

This is a regression.This does not affect UE5. Creating a function with parameter type TEnumAsByte<MyEnum> will crash while compiling. In 4.26 and UE5 the code compiles without issue, and the user ...

FSlateApplication::OnControllerAnalog triggers a MouseLeftClick event to be added to the input stack.

UE - Gameplay - Input - Jun 3, 2016

It appears that FSlateApplication::OnControllerAnalog triggers a left mouse click to occur on mobile platforms. If developers haven't properly avoided hooking up delegates to the InputComponent for ...

Blueprint Cannot Give Niagara CPU Access To Skeletal Meshes Added From Blueprint

UE - Niagara - Apr 4, 2019

When a user tries to add a skeletal mesh component to a blueprint with a niagara system to use the skeletal mesh with that niagara system, the niagara system will stop rendering because it does not ...

Physics enabled Child Actor components that spawn with with a delay, always spawns at world origin

UE - Gameplay - Jun 3, 2016

Physics enabled Child Actor components that spawn with with a delay, always spawns at world origin **This is a regression. It was working in 4.11.2 Could also be related to: [Link Removed] User D ...

Non-Struct CDO component properties display incorrectly in the property editor.

UE - Gameplay - Blueprint - Aug 17, 2016

UObjectProperty properties within a UActorComponent class aren't exposed for editing in the Details panel when choosing to edit native component defaults in the BP editor. ...