Niagara Mesh Renderer registers NumParticles x NumMeshVariants TLAS instances

UE - Rendering - Graphics Features - Ray Tracing - May 28, 2026

When using the Niagara Mesh Renderer with multiple mesh variants selected via MeshIndex, the number of TLAS instances allocated is NumParticles × NumMeshVariants and enabling the Path Tracer can ca ...

Regression - Nested scene component subobjects are no longer being registered when the owning scene component is added to an existing Actor instance as an instanced component.

UE - Gameplay - Components - Nov 16, 2016

This is a regression that was introduced with changes made to address issues with native vs. non-native component registration at Blueprint construction time ([Link Removed]). Prior to those change ...

If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.

UE - Framework - Blueprint Editor - Dec 17, 2025

Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...

Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI

UE - Runtime - Deformable - Apr 22, 2025

Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI. The licensee noticed that the Trailing event is not available to BPs. It's expected that the same data avail ...

Regression: Several project settings, especially from built-in Plugins, are being silently erased when previously they were not, which is perceived as a bug

UE - Core - Systems - Feb 28, 2025

In UE's Project Settings, some pages are saved automatically to the project's "Config/Default<CATEGORY>.ini" file (meant to be version-controlled) on every change. Other pages have buttons "Set as D ...

Editor crash when a spline component is added to a blueprint and compiled

Tools - Sep 7, 2016

Most recent user affected CL: 3106830 (4.13.0) Error message: Access violation - code c0000005 (first/second chance not available) Source Context: SelectedKeys = SplineVisualizer->GetSelectedKey ...

[CrashReport] UE4Editor_D3D11RHI!TerminateOnDeviceRemoved() [d3d11util.cpp:176]

UE - Graphics Features - Nov 18, 2016

Error message: Fatal error: [Link Removed] [Line: 176] Unreal Engine is exiting due to D3D device being lost. (Error: 0x887A0006 - 'HUNG') Source Context: 161 162 const TCHAR* Rea ...

Internal Compile error received from rearranging Format Text nodes

UE - Gameplay - Blueprint - Dec 18, 2014

Internal Compile error received from rearranging Format Text nodes Output Log of Error: LogBlueprint:Error: [compiler] Error Internal compiler error inside CreateExecutionSchedule (site 2); please ...

IOS crash disabling idle timer when closing the app

UE - Platform - Mobile - Apr 29, 2020

Licensee report of crash during shutdown due to setting [UIApplication sharedApplication].idleTimerDisabledbeing from the Game thread. Grouped together with others items in [Link Removed] ...

Custom UVs don't store information properly in layered materials.

UE - Rendering - Architecture - Materials - May 9, 2022

[Link Removed] I have this set up so that FX artists can stack UV manipulations, so I don't want to just have all the UV manipulation in the layer with the base color, even though that does give me ...