Missing PSO Precaches in the engine

UE - Rendering - Architecture - RHI - Aug 20, 2025

A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...

Removing a parameter from a blueprint function in a library can cause actor classes calling it to lose their parent or instance data

UE - Gameplay - Blueprint - Oct 4, 2018

Compile errors caused by an actor calling a function with something hooked up to a removed parameter can cause that actor to lose it's place in the hierarchy. Typically, the actor will be fixed once ...

AttachToComponent replication snapping to position instead of keeping relative location

UE - Networking - Feb 15, 2019

When using AttachToComponent at runtime, the attachment does not replicate properly for some clients. The relative transform/rotation is not maintained. The user who reported this issue mentioned th ...

Some landscape grass instances floating when generated on AMD cards under OpenGL

UE - Graphics Features - May 15, 2015

User is reporting grass at the edge of their landscape being generated floating in the air on a Mac Pro with AMD GPUs. I have been unable to repro this on my Mac Mini with Intel Graphics HD 4000. Q ...

Enum Compare Condition causes crash when resetting default value of right field in State Tree's Enter Conditions

UE - AI - StateTree - Feb 11, 2026

In FStateTreeCompareEnumCondition::GetDescription, the Left.Enum value is mistakingly used when setting the RightValue. This causes crashes when resetting the default value of the Right field in an ...

Disabling Editor Sounds Doesn't Prevent Compile Sound From Playing

Tools - Nov 10, 2015

Disabling the Editor Sounds under Editor Preferences->Level Editor->Miscellaneous->Sound->Enable Editor Sounds doesn't stop the Compile sound from playing when you click the Compile button in the ed ...

Custom iOS icons don't appear on device for Windows BP projects (Binary Build)

UE - Platform - Mobile - May 4, 2018

iOS icons have stopped working for Windows BP projects again; this does not occur on Mac. It also does not occur when using a source build from p4 (only on a binary build from the launcher). Note t ...

Dirty Actors in WP lose their actor folder in the outliner (and cause warnings) on PIE

UE - World Creation - Worldbuilding Tools - World Partition - Mar 20, 2023

From Licensee: You can reproduce this in stock by doing the following:Make a new 5.1 project with a new WP map (it can be empty)Put some actors in some folders in the outliner and save them/reload ...

A SkeletalMesh component will spawn in rotated when setting the skeletal mesh and simulating physics on Begin Play

UE - Simulation - Physics - Jun 28, 2016

A SkeletalMesh component will spawn in rotated when setting the skeletal mesh and simulating physics on Begin Play Adding a Delay between SetSkeletalMesh and SetSimulatePhysics will correct the iss ...

A replicated Timeline's Finished output does not fire on the Client if the Server changes the Timeline Length to a shorter duration

UE - Networking - Jan 28, 2016

A replicated Timeline's Finished output does not fire on the Client if the Server changes the Timeline Length to a shorter duration. Test project attached. Reproduced in 4.9.2 binary, 4.10.2 binar ...