Static/stationary child actor components are invisible and/or move position when placed inside a dynamically loaded level

UE - Framework - Components - Oct 31, 2024

When loading a non-world partitioned level into a persistent world partitioned level, parent actors with child actor components within the loaded map will move position or become invisible. Within t ...

Make literal container nodes (e.g. MakeArray) do not cast object ref output terms linked to interface-typed input pins.

UE - Framework - Blueprint - Jan 28, 2023

As with most nodes, object reference outputs can be directly connected to interface-typed inputs on "make container" nodes (e.g. "MakeArray") if the object's class type implements the interface clas ...

Dangling pointer + mem corruption related to OwnerLastRenderTimePtr

UE - World Creation - Worldbuilding Tools - Mar 16, 2026

We've been seeing asserts and crashes related to OwnerLastRenderTimePtr. We've traced this to the mentioned pointer ending up dangling after using UActorComponent::Rename() on primitive components t ...

[CrashReport] UE4Editor_Engine!FPhysScene::SyncComponentsToBodies_AssumesLocked() [physscene.cpp:1271]

UE - Simulation - Physics - Dec 1, 2017

This is a common crash in 4.18 and 4.18.1. The callstack shares similarities to [Link Removed], although that has been confirmed fixed in 4.18. Included in the same crashGroup are also a few Ensur ...

Crash when enabling dynamic branch on static switches in Post Process Materials

UE - Rendering - Architecture - Materials - Jun 28, 2023

[Link Removed] Some functions to access parameters don't take into account the newly added runtime static switch parameters. It should be straightforward to fix these up: void UMaterialInstance:: ...

In 5.6, bWarningsAsErrors does not work with clang

UE - Core - Cpp Tools - UnrealBuildTool - Sep 20, 2025

In 5.6, many warnings and errors specify their command line arguments to the compiler with these new C# attributes:    [WarningsClangToolChain(["-Wno-date-time"], ["-Wdate-time", "-Wno-error=date-ti ...

Instanced Actors: PCG on RuntimeGrid "None" assigns created IAManagers RuntimeGrid "MainGrid", causing cross-grid reference

UE - Graphics Tools - PCG - Graph - May 30, 2026

Context PCG can be used to spawn Instanced Actors via the PCG IA Interop plugin, that makes Spawned Instanced Actors available as node. When a PCGActor placed in the level runs a PCG graph that spa ...

MaterialTextureScale calculated incorrectly for materials with WorldPositionOffset

UE - Rendering - Architecture - Materials - Apr 16, 2024

When a Material uses WorldPositionOffset, the MaterialTextureScale is calculated incorrectly because FMaterialUtilities::ExportMaterialUVDensities() calls FMeshRenderer::RenderMaterialTexCoordScales ...

Multiple Materials not assigned to Mesh on Import

UE - Editor - Content Pipeline - Import and Export - Jan 6, 2017

Not all material elements are created and assigned to the static mesh using multiple materials. With the attached mesh, only the first element is created and the other two are left non-existent. I c ...

TextRenderComponents not parallel safe. Can cause crash

UE - Graphics Features - Feb 28, 2017

Licensee has reported intermittent crashes when loading a map that contains Child Actors with Text Render Components. When the child actor blueprint is spawned all of the text render components st ...