Sequencer custom task scheduler hangs with more than 512 tasks (TDynamicSparseBitSet::IsBitSet and operator|=)

UE - ACT Character - Sequencer - Oct 12, 2026

With Sequencer.CustomTaskScheduling enabled, a task graph with more than 512 tasks can hang FEntitySystemScheduler::ExecuteTasks. Reported by a licensee, they hit it with a 528 task graph under Clan ...

SetDisableRetargeting does NOT work correctly for packaged project

UE - Runtime - Animation - Jan 4, 2023

For example in cutscenes, the users use FBoneContainer::SetDisableRetargeting to temporarily use a specific shared animation without retargeting. But the function does not work correctly. We can fi ...

Cull Distance Volumes do not effect Blueprints or Skeletal Mesh Actors

UE - Graphics Features - Jul 31, 2014

CHANGELIST: 2181118 BRANCH: UE4 https://udn.unrealengine.com/questions/166371/cull-distance-volume-bug.html DESCRIPTION: Cull distance volumes don't seem to cull blueprints or meshes inside a bluep ...

Scene Color node with UV input on a transparent material renders incorrectly in stereo

UE - Platform - XR - Jan 19, 2021

From Licensee: When we have Instanced Stereo enabled, all our materials that use Scene expression nodes (SceneDepth, SceneColor, etc...), render incorrectly in the right eye. It only happens to the ...

Combined Translate and Rotate Mode broken when using Local Space

UE - Editor - Dec 22, 2023

From UDN: When using the Combined Translate and Rotate Mode we run into an issue where the rotation arrow moves twice as fast as the coordinate frame. The object itself rotates correctly, but if we ...

BP - Nativization will fail at cook time if a BP class and a User-Defined Structure reference each other.

UE - Gameplay - Blueprint - Apr 20, 2017

Note: This happens with "Exclusive" nativization mode as well. This occurs because the nativized UDS 'GetDefaultValue()' method is generated into a .h file rather than a .cpp file. This creates a c ...

Variant manager crash in UPropertyValue::HasValidResolve

zComponent - Archive - Nov 21, 2024

in the past we have reported a lot of VM related bugs which got fixed over time. Unfortunately, I think we have another one. Right now we're using 5.0.3 binaries from the launcher. Now the pro ...

Nanite: unused VertexInterpolator node disables Opacity Mask (material renders opaque)

UE - Rendering - Architecture - Jun 8, 2026

On Nanite meshes, placing a VertexInterpolator node in a material graph without using it (unconnected, or routed through a disabled static switch) silently breaks the Opacity Mask and the material r ...

ApplicationReceivedScreenOrientationChangedNotificationDelegate does NOT work properly on Android

UE - Platform - Mobile - Aug 5, 2019

ApplicationReceivedScreenOrientationChangedNotificationDelegate supports iOS but not Android. Probably, Java_com_epicgames_ue4_GameActivity_nativeOnConfigurationChanged should be useful for fix thi ...

ensure(false) being fired in FGenericParticlePairMidPhase::FindOrCreateConstraint from key collision

UE - Runtime - Simulation - Jan 27, 2025

ensure(false) being fired in FGenericParticlePairMidPhase::FindOrCreateConstraint from key collision. The licensee reports one of their users reported this issue and they were able to reproduce a fe ...