Huge performance hit when recording a demo (demorec)

UE - Networking - Jun 3, 2019

The current engine version (4.22) seems to suffer a huge performance hit when using the demo recording (demorec) feature. This issue is present in both the editor and the packaged game (developer bu ...

Emissive material lighting falloff regression in GPU Lightmass

UE - Graphics Features - Sep 12, 2023

Forum user noted that emissive lighting being built with GPU Lightmass is in fact being built, just not around the mesh, but in a larger radius and with reduced strength compared to 5.1.1. They foun ...

Texture Streaming can randomly streams in all Mips, causing large memory spikes

UE - Rendering - Architecture - RHI - Dec 5, 2025

A possible race condition allows texture instance views to read uninitialized bounds, causing either garbage or zero screen size values to be returned by FRenderAssetInstanceAsyncView::GetRenderAsse ...

ResavePackages commandlet with Build Lighting applies level transform each time

UE - Foundation - Core - Cooker - Sep 13, 2016

While using the commandlet for RebuildPackages with -BuildLighting and having any sub-levels with level transforms will be added to the current position each time this commandlet is run. As an exa ...

Camera attached to a Spring Arm jitters when put at a +90 or -90 degree angle on the Y axis.

UE - Gameplay - Nov 18, 2016

When a camera attached to a spring arm is turned at a +90 or -90 degree angle in the Y Axis (can't go any further) and turned, it can jitter and cause visual issues. Note: This occurs in the base ...

Blueprint Library plugin set to 'Runtime' doesn't work in Standalone/packaged builds if used inside of the 1st Person Character BP

UE - Foundation - Cpp Tools - UnrealBuildTool - Nov 18, 2016

Blueprint Library plugin set to 'Runtime' doesn't work in Standalone/packaged builds if used inside of the 1st Person Character BP. User Description: Blueprint libraries are still broken in the fi ...

Modulated shadows do not render in the correct area on older devices / versions of Android OS

UE - Platform - Mobile - Apr 5, 2016

This issue was reported by a user who was having issues with their modulated shadows showing up in random spots on their mobile devices. Their devices were a Samsung Galaxy Note 2 and a ASUS Zenfon ...

Event tick not firing when in an actor component that is added to an actor

UE - Gameplay - Blueprint - Aug 22, 2017

When using actor components, if you delete a node, such as event tick and then add it to an actor, even if you modify the component again, such as adding the event tick event back, the component wil ...

Generate Project Files process fails if SwarmAgent.exe is not present

UE - Foundation - Cpp Tools - Mar 5, 2019

This issue appears to be the result of the fix for [Link Removed] which removed RPCUtility from the Engine. A licensee noted that they were now seeing an issue when attempting to generate project fi ...

Reimporting an FBX causes invalid collision on Spline Mesh Components (Chaos)

UE - Editor - Content Pipeline - Import and Export - Nov 11, 2021

Reported in UDN: [Link Removed] Reimporting a static mesh asset from an FBX file causes collision to disappear on spline meshes referencing the static mesh asset. In investigating this in 4.27, I ...