Attaching a removed Actor in Sequencer causes a crash

UE - Anim - Sequencer - Jan 6, 2020

This is a regression from 4.23.1 (CL-9631420) where Sequencer just displayed the re-attached binding in yellow text instead of crashing. The user suggests that the deleted actor should be removed fr ...

Editor Crashes On Startup After Enabling Light Propagation Volume (LPV) With Forward Shading

UE - Graphics Features - Feb 20, 2017

After enabling Forward Shading that project can no longer operate while "r.LightPropagationVolume = 1" since it will crash immediately. ...

Xcode 8 Beta Toolchain Breaks InfiltratorDemo on AMD On 10.11.6

UE - Platform - Apple - Jul 27, 2016

InfiltratorDemo rendering is entirely broken on 10.11.6 using AMD GPUs when the shaders are compiled to byte code using the Xcode 8 Beta 2 toolchain. This does not appear to occur with the Xcode 7.3 ...

Level Sequence Actor- bTickWhenPaused is unsettable from the details view

UE - Anim - Sequencer - Aug 1, 2024

See UDN here: https://udn.unrealengine.com/0D5QP00000TtFaV0AV?fromCase=1 The issue is that in FMovieSceneSequencePlaybackSettings, the TickInterval struct is marked with an EditCondition to only be ...

[Groom] Very thin hair has incorrect raytraced shadow on edges

UE - Graphics Features - Lumen - Jun 8, 2020

This only happens when 1) Hair Width is very small. e.g. 0.01 in the example 2) Light has raytraced shadow and Samples Per Pixel has a value > 1. e.g. 8 in the example The problem seems to be rel ...

Client and server can both get stuck waiting for packet sequence history flush

UE - Networking - Sep 4, 2025

The issue occurs when both instances have a significant difference between their last sent and last ack'd sequence number, as they will begin waiting for the sequence history to be flushed for a pac ...

Twinmotion sign-in error when attempting sign-in inside app

TM - Core - May 18, 2026

Reported in SF [Link Removed] Attempting to sign into Twinmotion from within the TM 2026.1 editor results in a consistent sign-in error using the sign-in buttons. Initial sign-in during launch whe ...

Adding SmartObjectZoneAnnotationComponent to a blueprint actor causes a crash when building the package

UE - AI - SmartObject - Jan 30, 2025

If placing an actor with SmartObjectZoneAnnotationComponent added to blueprint actor in a level, it will crash when the level open. As a workaround, adding SmartObjectZoneAnnotationComponent to the ...

Spline don't deform landscapes in certain setups

UE - LD & Modeling - Terrain - Landscape - Dec 26, 2019

The splines do not deform the landscape when the path is made with a straight spline. When you move a spline point to bend the road it will deform the landscape, but the deformation accuracy seems t ...

Able to scale Math Hall graphs down to 0 which distorts them in ContentExamples

Docs - Samples - Sep 19, 2016

All of the graphs in the Math_Hall can be scaled down to 0 which causes the graphs to appear distorted. These should probably be clamped as 1 since scaling them down to 0 does not show any useful in ...