Physics Constraint Actor: When plasticity is enabled, Drive Position Target is reset to zero on constraint initialization

UE - Simulation - Core - Mar 5, 2026

When a Chaos joint constraint is first created, having linear/angular plasticity enabled will unexpectedly force its linear/angular drive position target to zero on initialization, disregarding the ...

Deferred spawned actors can receive BeginPlay before they are finished spawning

UE - Framework - Performance - May 18, 2023

Actors that are deferred spawned on BeginPlay can be added to the world while AWorldSettings::NotifyBeginPlay is still iterating the world's actors and dispatching BeginPlay. AActor::DispatchBeginPl ...

Mobile Previewer: Safe Zone Invalid Until Window Resize

UE - Platform - Mobile - Jul 12, 2021

When the Mobile Previewer loads, the Safe Zone widget is not working properly at startup, and requires a window resize to update to the correct Safe Zone. ...

Using dynamic bindings in a code class will result in the bindings becoming a permanent part of any Blueprint created from that class if a hot reload is performed.

UE - Foundation - Core - Mar 26, 2015

If dynamic bindings are being used in a custom code class from which Blueprints are derived, any hot reload will make the bindings a permanent part of the Blueprint and they cannot be removed or cha ...

Internal Compile error received from rearranging Format Text nodes

UE - Gameplay - Blueprint - Dec 18, 2014

Internal Compile error received from rearranging Format Text nodes Output Log of Error: LogBlueprint:Error: [compiler] Error Internal compiler error inside CreateExecutionSchedule (site 2); please ...

Crash occur when loading AInstancedPlacementPartitionActor

UE - Editor - Workflow Systems - May 17, 2022

Crashes when loading an actor that inherits from AInstancedPlacementPartitionActor. There is a serialization size mismatch. ...

IOS crash disabling idle timer when closing the app

UE - Platform - Mobile - Apr 29, 2020

Licensee report of crash during shutdown due to setting [UIApplication sharedApplication].idleTimerDisabledbeing from the Game thread. Grouped together with others items in [Link Removed] ...

Custom UVs don't store information properly in layered materials.

UE - Rendering - Architecture - Materials - May 9, 2022

[Link Removed] I have this set up so that FX artists can stack UV manipulations, so I don't want to just have all the UV manipulation in the layer with the base color, even though that does give me ...

A welded hierarchy blocks updates to collision settings on all but the root primitive. Calling SetCollisionResponseToChannel on the children won't work.

UE - Simulation - Core - Nov 22, 2024

A welded hierarchy blocks updates to collision settings on all but the root primitive. Calling SetCollisionResponseToChannel on the children won't work. The licensee noticed that IPhysicsProxyBase* ...

Alembic Geometry Cache crash with multiple meshes

OLD - Anim - Sep 1, 2016

Importing an Alembic geometry cache will cause a crash with multiple assets. Test asset attached that can reproduce this. When I tried with a couple of simple shapes from 3Ds Max I did not get the ...