Client PlayerState is null on joining online session

UE - Networking - Jul 31, 2015

APlayerController::ClientStartOnlineSession() checks PlayerState at the start of a game after loading a level. Due to time needed to load in, client player state may may return NULL ...

Rearranging the position of enumerators in an Enum BP will change references to the enumerators inside Data Tables based on position rather than value

Tools - Nov 12, 2015

Rearranging the position of enumerators in an Enum BP will change references to the enumerators inside Data Tables based on position rather than value. Reproduced in 4.8.3 binary, 4.9.2 binary, 4.1 ...

Hierarchical LODs used with Precomputed Visibility cause actors to occlude that should not behind translucent materials

UE - Graphics Features - Jul 6, 2016

When using Precomputed Visibility in conjunction with HLODs and translucent materials without them culling actors occluded by the translucent material. The example gif attached shows that the base ...

Crash occurs when opening a Blueprint that contains a variable that is of a type of a child of the Blueprint, as well as a component containing instanced UObjects

UE - Gameplay - Blueprint - Dec 23, 2016

A crash that is possibly the result of a circular dependency can occur if a Blueprint containing an ActorComponent with instanced UObjects and a variable that is a type of a child of itself is opene ...

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 ...

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 ...

Parent component visibility in a child blueprint isn't reflected in a launched project.

UE - Gameplay - Blueprint - Mar 5, 2015

Parent component visibility in a child blueprint isn't reflected in a launched/packaged project. ...

After breaking a level instance without Actor Folders, moving its actors between folders of the world-partition map does not work correctly

UE - World Creation - Worldbuilding Tools - World Partition - Jan 29, 2024

If a standard level (without Actor Folders enabled) is added to a world-partition map (with Actor Folders enabled) as a Level Instance, and then that instance is "broken" so that its actors are inco ...

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 ...

Gameplay Tags with the string "None" as any of its hierarchical node identifiers behave incorrectly (because of an incomplete generated FGameplayTagContainer::ParentTags array)

UE - Gameplay - Nov 19, 2024

Currently, using the string "None" as a hierarchical node identifier inside a Gameplay Tag (for example "A.B.C.None.D.E.F") is not disallowed by the engine, but results in some incorrect behaviors. ...