Duplicating a blueprint that implements an interface and then removing that interface will cause compile errors that don't occur if the interface was removed from the original BP

UE - Gameplay - Blueprint Editor - Aug 1, 2020

See steps to reproduce. Looks like the fixup when saying Yes to "Would you like to transfer the interface functions to be part of your blueprint" doesn't work correctly on the duplicated BP. Inter ...

[MetaSounds][Stereo Mixer] - When changing the gain on the Right channel dynamically, the output has clicks and pops

UE - Audio - MetaSounds - Mar 31, 2022

When changing the right channel gain of the stereo mixer at runtime, it generates clicks and pops in the output. ...

Masked TwoSided material causing lumen direct lighting to leak through walls

UE - Graphics Features - Lumen - Apr 23, 2024

It appears that LumenScene's Hardware Ray Tracing is causing light leaking into a sealed room (which should be perfectly black). This bug does not appear to happen on AMD GPUs. ...

Custom node not working with material attributes

UE - Rendering Architecture - Materials - Jul 15, 2024

Using Material Attributes as an input to a Custom Expression causes the HLSL Translator to create multiple CustomExpression# functions, for each used member of the Material Attributes, rather than u ...

Packed level actors and Level instances are sometimes not included in HLOD build on a World Partition Level

UE - World Creation - Worldbuilding Tools - HLOD - Mar 14, 2025

Context World Partition - Hierarchical Level of Detail (HLOD) system uses custom HLOD Layers to organize large amounts of Static Mesh Actors and generate a single proxy mesh and Material. Problem T ...

Audio Components ignoring Start Time set by Play node on Android

UE - Audio - Jul 15, 2015

Setting the start time within the Play node for an audio component does not function when deploying to Android. The set up works fine when playing on the PC, and the sound functions on the Android ...

Building Lighting will Generate Additional Lightmaps after Rotating Lightsource

UE - Graphics Features - Jul 7, 2015

Lightmap sizes seem inconsistent after rotating a light source and rebuilding the lighting. This causes concern about file sizes when packaging the project that is using baked static lighting. The ...

Creating an exposed variable does not always update correctly to the bp's Details panel

UE - Gameplay - Blueprint - Feb 20, 2015

Creating an exposed variable does not always update correctly to the bp's Details panel. They will show as having multiple values until the bp is clicked off and back onto. ...

The Add node does not update in the Construction Script

UE - Gameplay - Blueprint - Feb 28, 2015

The Add node does not update in the Construction Script. Reproduced in 4.7.1 binary and Main (//depot/UE4/Promotable-CL-2455917) ...

RepNotify variables passed by reference to a function or macro that then change the value of the variable do not trigger the OnRep function on the Server

UE - Networking - Jul 1, 2015

RepNotify variables passed by reference to a function or macro that then change the value of the variable do not trigger the OnRep function on the Server. This is inconsistent with the behavior with ...