Unable to use TWeakObjectPtrs for the optional Old value for a repnotify function

UE - Foundation - Cpp Tools - UnrealHeaderTool - Oct 8, 2018

A user has reported that Unreal Header Tool fails to parse a rep notify function properly when the optional parameter for the Old value is populated with a TWeakObjectPointer. Example of errors:Sev ...

Drag and drop does not work from a window created with PySide

UE - Editor - Workflow Systems - Feb 5, 2026

The cursor position is no longer updated during drag and drop, so drag-over events cannot respond correctly. Commenting out the following code in WindowsCursor.cpp works as a workaround ( the behavi ...

MemReport does not seem to respect mesh streaming

UE - Rendering - Architecture - Aug 6, 2024

The function "FStaticMeshLODResources::GetResourceSizeEx(...)" does not take into account that the buffers might be emptied, due to Mesh Streaming. This causes "obj list" to report sizes larger than ...

Implied Decal Blend Modes don't properly account for Material Attributes usage

UE - Graphics Features - Sep 28, 2021

I've attached a project with the necessary materials that demonstrate this issue. I would expect that just because a Set Material Attributes node is inside a material graph it wouldn't affect the de ...

Particles Do Not Obey Lighting Channels

UE - Niagara - Apr 17, 2018

Particle systems ignore lighting channels - no matter what channel a light is on (even if no channels are selected), it will affect lit particles. Changing lighting channels on the particle itself h ...

SplineMeshComponent's collision will start to distort the longer the Spline becomes

UE - Gameplay - Nov 30, 2016

SplineMeshComponent's collision will start to distort the longer the Spline becomes This is a regession. It was working in 4.13.2-3172292 User Description: When drawing out a long spline mesh ( r ...

World partition mini map fails to build with an Unhandled Exception while using r.Raytracing.Nanite.Mode=1

UE - Graphics Features - Jan 31, 2023

This is a regression. Tested in //UE5/Release-5.0 CL20979098 Build mini map fails with an Unhandled Exception while r.Raytracing.Nanite.Mode=1 is enabled in the DefaultEngine.ini. ...

Sub Surface Shading Model has Strange Blotch Color Artifacts when Used with a Ambient Cubemap

UE - Graphics Features - Sep 23, 2019

Sub surface shading model has strange blotch color artifacts when used with ambient cubemap. Since the subsurface profile shading model can't be used with ambient cubemap I wanted to use the regular ...

Duplicating many Actors at once in a Level Instance while in Level Instance Edit will result in a jumbled mess of Actors on the Persistent Level

UE - World Creation - Worldbuilding Tools - Level Instances - Feb 12, 2025

Duplicating many Actors at once in a Level Instance while in Level Instance Edit will result in a jumbled mess of Actors on the Persistent Level. The licensee has encountered this in Unreal 5.4 and ...

Dynamic Parameters do not function in Beam Emitters

UE - Graphics Features - Apr 10, 2015

Transfered Issue from TTP # 298314, originally opened in TTP on 6/3/2013 and updated with Answerhub post information on 5/18/2014 Dynamic Parameters cannot be used with a Beam Emitter, they pass no ...