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 ...

Instanced Static Mesh does not apply World Aligned Material correctly

UE - Graphics Features - Aug 22, 2016

If you apply a material that uses World Aligned Blend to an instanced static mesh, it will display differently than an non-instanced static mesh with identical settings. They only look identical if ...

mobile DOF setting is not applied when play on standalone mode

UE - Platform - Mobile - Feb 20, 2023

In 5.0, the mobile depth of field settings were correctly reflected when running standalone. However, in 5.1, the DOF doesn't appear to be working correctly and the focus is off, causing a blurry im ...

FX.TestGPUSort fails on Vulkan

UE - Niagara - May 5, 2025

“FX.TestGPUSort” fails on both PC Editor and Android with Vulkan RHI. ...

Fringe Saturation in Post Process Volume not functioning

UE - Graphics Features - Jul 27, 2015

Setting the values for Fringe Saturation within the Post Process Volume does not seem to have any visual change. The documentation suggests that changing the Fringe Saturation will either increase ...

When multiple HLODs are set, the transition does not occur correctly

UE - Graphics Features - Aug 30, 2019

The [bIsVisible] flag is set to [1] by the following judgment.const bool bIsInDrawRange = DistanceSquared >= Bounds.MinDrawDistanceSq * HLODState.FOVDistanceScaleSq; Judging from this code, I bel ...

Child Actor component is duplicated in Standalone Game

UE - Gameplay - Jan 12, 2017

Child Actor component is duplicated in Standalone Game. No other play modes or packaged game are affected. The additional actor will disappear after 1 minute. *This is a regression: Doesn't occur ...

(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 ...

FMultiReaderSingleWriterGT isn't thread safe

UE - Foundation - Core - May 17, 2016

From https://udn.unrealengine.com/questions/292741/fmultireadersinglewritergt-isnt-thread-safe.html: I've found that FMultiReaderSingleWriterGT has at least 2 bugs: The one that caused a deadlock ...

Foliage LODs do not appear to use the base LODs lightmap any longer

UE - World Creation - Worldbuilding Tools - Foliage - Dec 16, 2016

LODs used with the Foliage Tool are no longer being shadowed accordingly with their baked lighting from their base LOD. Originally they would stay consistently lit, where as now the lower LOD transi ...