Calling UMoverComponent::IsModifierActiveOrQueued() immediately after calling UMoverComponent::K2_QueueMovementModifier() will return false

UE - Gameplay - Player Movement - Mover - Mar 10, 2025

Calling UMoverComponent::IsModifierActiveOrQueued() immediately after calling UMoverComponent::K2_QueueMovementModifier() will return false. Checking the code, IsModifierActiveOrQueue() calls FindMo ...

Crashes when attempting to use an Instanced Struct inside Control Rig / Rig VM

UE - Anim - Rigging - Control Rig - Mar 17, 2025

Currently, the Control Rig Editor allows the user to use the "Instanced Struct" type, for example for a variable or function input/output. However, this type does not seem to be properly supported ( ...

FJsonObjectConverter::ExportCallback_WriteISO8601Dates allows for writing FDateTime that does not have ticks

UE - Core - Systems - Mar 12, 2025

Context: `FJsonObjectConverter` is a built-in UE class that makes it easy to convert JSON objects to and from UStructs, including `FDateTime`, which implements a date and time. Problem: An uniniti ...

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined property (bSimulatePhysics), throws an error

UE - Framework - Apr 15, 2025

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined class property (bSimulatePhysics), throws an error in the logs: LogEditCondition: Error: EditCondition pa ...

FStateTreeExecutionContext::GetDebugInfoString() outputs wrong info and crashes when using linked state trees

UE - AI - Debugging - Apr 17, 2025

When using State Trees, the AI Debugger can be accessed during play to show information about their current execution state. If a behavior tree is currently in a state that references a linked tree, ...

FSubobjectData::SetupAttachment() receives SocketName as a parameter but ignores it.

UE - Framework - Components - Apr 17, 2025

When using the Subobject Data Subsystem in C++, method FSubobjectData::SetupAttachment() can be used to help attaching a component to a parent at a given socket. This function receives SocketName as ...

Sequence with restore state set is causing a "Fatal world leaks detected" crash

UE - Anim - Sequencer - May 14, 2025

We recently had a few occurrences of crashes caused by a "Fatal world leaks detected" error when unloading a level (in a packaged game and in editor). I tracked down what was keeping a references t ...

Rendering of a Text Widget with Outline does not track LayerId correctly

UE - AI Workflows - UI Systems - May 27, 2025

Text widget with Outline uses 2 LayerId levels to draw the outline and the text glyphs. This can be seen in function FSlateElementBatcher::AddShapedTextElement(), where lambda BuildFontGeometry() is ...

PlayerCameraManager->OnBlendComplete() delegate not getting called

UE - Gameplay - Gameplay Cameras - May 29, 2025

The PlayerCameraManager->OnBlendComplete() delegate is not getting called when running a game in a standalone network mode without any networking. ...