[AI] Debug Render Scene Proxy hits ensure for registering a delegate twice during level streaming.

UE - AI - Debugging - Aug 31, 2022

Description from licensee: We're seeing an ensure get tripped up in FDebugRenderSceneProxy that says "DrawDelegate is already Registered!". Debugging the issue, we have confirmed that the DrawDeleg ...

When using 'r.VT.SplitPhysicalPoolSize 64' with nanite meshes, mesh painting does not update in real time (only updates after stroke finished), duplicates mesh painting across separate instances of a mesh, and sometimes doesn't show up in PIE.

UE - Rendering - Architecture - Mar 3, 2025

When using Mesh Painting on nanite meshes in 5.5 with 'r.VT.SplitPhysicalPoolSize' set to non-zero values (e.g. 16, 64), several issues occur, such as: 1. Painting doesn't update in real time (only ...

When multiple actors are selected, they have different undo behavior in the details panel

UE - Editor - Verse Class Editor - Nov 15, 2021

When the text in spinbox has focus, it doesn't get the change notification externally. It may also be worth noting that ctrl z or ctrl y also do not get bubbled up to undo the text box values. It a ...

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables

UE - Gameplay - Blueprint - May 26, 2015

Compiler error after changing the class in a Spawn Actor from Class node, undoing with Ctrl + Z, refreshing the node, and reconnecting exposed variables. "Error Internal compiler error inside Creat ...

In 5.6, bWarningsAsErrors does not work with clang

UE - Core - Cpp Tools - UnrealBuildTool - Sep 20, 2025

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes:    [WarningsClangToolChain(["-Wno-date-time"], ["-Wdate-time", "-Wno-error=date-ti ...

UAT searches wrong root folder for include paths specified in .Build.cs

UE - Foundation - Cpp Tools - Automation Tool - Jun 21, 2018

When running the BuildPlugin command on a plugin in 4.20 preview 3, UAT is not detecting the correct root folder for the relative include paths specified in a module's .Build.cs. Expected: UAT is a ...

UAbilityTask_SpawnActor::BeginSpawningActor may return true when SpawnedActor contains stale value

UE - Gameplay - Gameplay Ability System - Mar 15, 2026

UAbilityTask_SpawnActor::BeginSpawningActor assumes the incoming AActor*& SpawnedActor parameter is nullptr if no actor was spawned, but it does not initialize the parameter at the start of the func ...

Static light contained in a blueprint will need lighting rebuilt each time the project is reopened

UE - Gameplay - Jun 29, 2017

Static light contained in a blueprint will need lighting rebuilt each time the project is reopened. This only seems to occur for a static light that is parented to a static mesh and then that static ...

Unreal Editor 5.4.4 crash when reproducing a LevelSequence in loop while PIE.

zComponent - Archive - Sep 9, 2024

A crash inside Unreal Engine Editor version 5.4.4 occurs when reproducing a Level Sequence while in PIE. This issue is a regression. It only crashes in version 5.4.4. It was working correctly in ver ...

[CrashReport] Assertion failed: !PinRef->bWasTrashed | UEdGraphPin::SerializePin()

UE - Gameplay - Blueprint - Aug 29, 2017

This is a common and longstanding crash that has occurred since at least 4.15 and affected nearly 500 users. The CrashGroup was previously linked to [Link Removed], but that had specific repro step ...