Always Relevant actor may replicate incorrect movement mode when the walkable floor becomes irrelevant

UE - Gameplay - Player Movement - Feb 26, 2024

When the character class is set to always relevant, if a client travels very far away from another character, such that the character is relevant but the component they're standing on is not (but al ...

FBlackboardKeySelector filters aren't applied when recompiling blueprint if a behavior tree asset containing the blueprint added as a service is closed, or if the blueprint is reparented.

UE - AI - BehaviorTree - Sep 24, 2025

Context In Behavior Trees, BT Services can be added to nodes. Those services can have configurable FBlackboardKeySelectors. BlackboardKeys are variables on a blackboard that the behavior tree can r ...

Renaming a Blackboard Key removes it's references in the Behavior Tree

UE - AI - Jan 27, 2015

Renaming a Blackboard Key removes it's references in the Behavior Tree ...

[CrashReport] UE4Editor_Renderer!FMaterialShader::SetParametersInner<FRHIVertexShader * __ptr64>() [shaderbaseclasses.cpp:181]

UE - Graphics Features - Jun 19, 2018

No user comments in crash group 172 const bool bOverrideSelection = 173 GIsEditor && 174 !View.Family->EngineShowFlags.Selection && 175 (MaterialRenderProxy- ...

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 ...

Collision of child actor doesn't rotate if the parent is simulating physics

UE - Simulation - Physics - Aug 11, 2015

Collision of child actor doesn't rotate if the parent is simulating physics. This was an old bug that an AnswerHub user reported back in 4.9 but now a licensee is reporting this same behavior in 4.1 ...

Hidden enumerator variables can cause the enumerator to become broken with the Select node in blueprints

UE - Gameplay - Blueprint - May 26, 2015

If a user makes an enumerator in C++ and sets one of the variables to Hidden and doesn't make it the last variable of the enum, it will cause issues with the numbering of the enum when using the Sel ...

ChaosCacheManager is not properly recording the state of each particle when toggling Fields and Anchor Fields in the scene.

UE - Simulation - Visual - Oct 22, 2024

ChaosCacheManager is not properly recording the state of each particle when toggling Fields and Anchor Fields in the scene. During my investigations I've noticed that ChaosCacheManager does not reco ...

Internal Compiler error when calling a custom enum in a struct from a blueprint macro

UE - Gameplay - Blueprint - Aug 6, 2015

If a macro is referencing a custom enum within a struct and compiled after another output pin is removed, an internal compiler error will appear and the blueprint will not compile. ...

The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors

UE - Simulation - Visual - Oct 15, 2024

The Remove-On-Break (ROB) feature, set on Fracture Mode on Geometry Collections (GC), was supposed to make the particle shrink until it vanishes. When the GC goes to sleep the shrinking stops and sh ...