DDC corruption creates incorrect pasted topology when using Landscape Copy / Paste Tool

UE - LD & Modeling - Terrain - Landscape - Apr 3, 2017

I noticed that the copy and pasted section of the level was being painted while I was painting a nearby section of the level. This weird yellow color appeared and I undid and redid the paint to make ...

Foliage: Speed tree wind is reset for every add/remove/update on instances

UE - World Creation - Worldbuilding Tools - Foliage - Jul 10, 2018

Foliage: Speed tree wind is reset for every add/remove/update on instances What is happening:When we invalidate the render state, proxy are recreated, causing the wind to be removed and add again, ...

World Partition - Deleted actors can become unloaded prior to saving

UE - World Creation - Worldbuilding Tools - World Partition - Apr 11, 2025

In world partition levels, deleted actors can become unexpectedly unloaded prior to saving, causing loss of work. Specifically, this issue occurs after the undo history has been cleared (either manu ...

'Get Distance Along Spline At Spline Point' Causes Crash

Tools - Jul 28, 2018

User reports that the reason for the crash is that because UpdateSpline is false on the AddSplinePointAtIndex blueprint node, this line is never called [ReparamTable.Points.Reset(NumSegments * Repar ...

[CrashReport] UE4Editor_UnrealEd!TArray<TSharedRef<FAssetThumbnailPool::FThumbnailInfo,0>,FDefaultAllocator>::AddUniqueImpl<TSharedRef<FAssetThumbnailPool::FThumbnailInfo,0> const & __ptr64>() [array.h:1805]

Tools - Sep 20, 2017

This is a longstanding crash that occurs with low frequency per release, but has affected 400 users since the 4.11 release. Unfortunately among all of them, only one has provided any description. ...

Simulated ability tasks not being cleaned up in UActorChannel::ReplicationMap

UE - Networking - Nov 20, 2018

I've noticed the issue occurring in both 4.20.3 (CL 4369336) and 4.21.0 (CL 4541578). The user on AnswerHub has also noticed the issue in 4.20.2 (CL unknown) and claims the issue did not occur in 4. ...

[CrashReport] ULevel::GetWorldSettings() - UMaterialInstanceThumbnailRenderer::Draw

Tools - Aug 29, 2017

This is a common assertion that has occurred since at least 4.14 and affected nearly 100 users. The callstack is similar to [Link Removed], which was marked fixed for 4.14. User DescriptionsUndoi ...

Cannot package an Engine plugin if another Engine plugin depends on the plugin being packaged

UE - Foundation - Cpp Tools - Plugin System - Nov 12, 2018

Packaging an Engine plugin fails if another Engine plugin lists that plugin as a private dependency. In the two attached plugins, PluginA lists PluginB as a required plugin in its .uplugin file, and ...

Incorrect Velocity Calculation at Animation Sequence Transitions in Level Sequence

UE - Anim - Sequencer - Feb 18, 2025

When adding an Animation Track to a Level Sequence and placing Animation Sequences back-to-back without gaps, the velocity can be miscalculated at the transition between sequences. This issue occur ...

Using GeoMerge on fragments of a GeometryCollection (GC) will create a new single particle while removing the old particles, but although you end up with less particles, the disk file size of the GC uasset increases.

UE - Simulation - Physics - Destruction - Nov 26, 2024

Using GeoMerge on fragments of a GeometryCollection (GC) will create a new single particle while removing the old particles, but although you end up with less particles, the disk file size of the GC ...