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 ...

Crash When Toggling Visibility of Level with Planar Reflection

UE - LD & Modeling - Terrain - Landscape - Mar 26, 2018

This crash occurs in 4.19 and 4.20 but not 4.18. Repro'd in 4.19.0-3944462 and 4.20.0-3955769 and 3964322. This is a regression. Per UDN licensee: When I'm showing/hiding levels in editor (in le ...

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 ...

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 ...

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. ...

Crash with for loop and TArray in constructor to generate multiple StaticMeshComponents

UE - Foundation - Core - Apr 20, 2015

Using a TArray to store multiple components being setup inside a for loop of a constructor will crash on project open. Crash Reporter: [Link Removed] ...

Decals custom depth/stencil side effect from Lumen

UE - Graphics Features - Oct 15, 2024

The order of passes related to Decal rendering (without the DBuffer) and CustomDepth is changed by the CVar "r.Lumen.AsyncCompute", even when Lumen is not enabled. This causes Decal Materials that ...

Max Pitch Angle does not correctly apply when utilized in procedural foliage volumes

UE - World Creation - Worldbuilding Tools - Foliage - Aug 27, 2015

Random Pitch Angle does not properly apply when called within a procedural foliage volume. ...

Renaming a Struct variable that is used in a Widget BP creates 'Warning: Unknown property in' warnings in the Output Log

UE - Gameplay - Blueprint - Apr 27, 2016

Renaming a Struct variable that is used in a Widget BP creates 'Warning: Unknown property in' warnings in the Output Log User Description: I think this should be brought up as these seems to be a ...