Editor becomes unresponsive when selecting BP_FirstPersonChracter0 while Playing in Editor with specific settings

UE - Editor - Jun 19, 2023

This is a regression. Testing //UE5/Release-5.1 CL23901901 When selecting BP_FirstPerconCharacter at run time in a project that has C++, Quality as Scalable, and Ray Tracing enabled the editor free ...

Translucent Dbuffer Decals not Rendering in Material Editor Preview Window

UE - Rendering - Architecture - Materials - Sep 30, 2016

Dbuffer decals with a Translucent Blend Mode are not rendering in the preview window of the Material Editor. Note I noticed the Default Blend Mode for Dbuffer Decals is set to Translucent now inste ...

NaN is handled differently when clamped on Windows and Android/iOS

UE - Platform - Mobile - Oct 18, 2017

NaN (Not a Number) is handled different when clamped on Windows and Android/iOS. If you clamp a NaN (Acheived by -3 ^ 0.2 in the reproduction project) from 0.0 to 1.0 and then print the result, you' ...

Artifacts in imported GLB and GLTF files

TM - Interoperability - Mar 10, 2025

Reported in SF [Link Removed] Client reports that many of their GLB and GLTF files they use appear with visual artifacts when imported to Twinmotion. These artifacts only appear in Twinmotion and n ...

Inconsistent events triggered by FlushProcessedKeys during keyboard hold input

UE - Gameplay - Input - Dec 20, 2024

Key repeats from the OS do not affect the EnhancedInput normally, but it causes inconsistent event triggers when FlushProcessedKeys is called with holding a keyboard key down. Removing references t ...

NDC Sorting Incorrect

UE - Rendering - Architecture - Niagara - Mar 12, 2026

Using the new NDC BP nodes in 5.7 causes sorting to break; one system, regardless of world placement, is always drawn over the other. Even when the viewpoint puts the dominant system in the foregrou ...

[AI] SmartObjectPersistentCollection produces errors during Map Validation

zComponent - Archive - Nov 18, 2025

SmartObjectPersistentCollection in 5.6 and later now give errors when the map validator runs due to referencing spatially loaded actors. This was working per licensee in 5.5. There was a change from ...

Lighting build fail due to failing to open channel for material data

UE - Graphics Features - Apr 21, 2017

Licensee reports lighting build fails for their specific levels which were created in 4.14.1 then moved to 4.15.1. Workaround: Setting LogLightmassSolver verbose level to Warning can show "Warning ...

GI not coming in with lighting build data when lighting built outside of main scene

UE - Rendering - Features - Mar 27, 2024

Volumetric Lightmaps are not shared between Persistent maps that have the same sublevels. Also observed in Release-5.4, CL 32500436 ...

Assert triggering when trying to copy-paste an empty CurveAtlasRowParameter node in the material editor

UE - Rendering - Architecture - Materials - Mar 25, 2024

A check happens when copy/pasting a Curve Atlas Row Parameter Expression that has no value. This behavior also exists on CL 32426910 of Release-5.4. ...