Inclusive Nativized Blueprints slower than Non Nativized Blueprints in packaged project

UE - Gameplay - Jul 1, 2019

When nativizing blueprints the packaged build of the project runs slower than a non-nativized version of the packaged project. Found in 4.22 CL#7053642 Reproduced in 4.21 CL#4753647, 4.24Main CL#7 ...

Sequencer Render: Animation not updating for a moment on camera cut

UE - Anim - Sequencer - Mar 17, 2017

When rendering from sequencer to an image sequence, character animation stops for 2 frames after a camera cut. This hitch does not occur when playing the sequence in PIE I've attached some sample d ...

Delegation issue with copied instances of a Trigger BP that is based off of the StaticMeshActor

UE - Gameplay - Blueprint - May 13, 2015

Delegation issue with copied instances of a Trigger BP that is based off of the StaticMeshActor parent class. If bp Trigger A is placed into the level and then 2 copies are made (B & C), when C i ...

Long thin spinning objects take too long to stop spinning

UE - Runtime - Simulation - Jun 5, 2023

See the SpinningObjectStability test map in the Physics Sandbox. [Link Removed] It's not clear if this is a bug or a side effect of some of our solver shortcuts (e.g., omission of the precession te ...

Android ETC2 Debug Builds Crash on Startup

UE - Platform - Mobile - Sep 9, 2020

Android apps build with the debug configuration on ETC2 will crash on launch. ...

Cable Actor becoming stiff when bound to two dynamic objects

UE - Runtime - Simulation - Jun 1, 2023

the cable actor does not dynamically deform when the cable actor's parent mesh moves. Instead, the cable actor becomes rigid between the meshes it's bound between. This bug does not occur in the fo ...

Crash Occurs When Attempting to Pass a Struct Containing an int64 into a Blueprint Function

UE - Gameplay - Blueprint - Feb 17, 2016

Attempting to pass a struct containing a variable of a type that is not compatible with blueprints into a blueprint function causes the editor to crash upon PIE. Found in 4.10.2 binary. Reproduced ...

Landscape displaces after converting file to Twinmotion 2026.1

TM - Core - Apr 23, 2026

Reported in SF [Link Removed] The client has a file from Twinmotion 2025.2 that contains a sculpted landscape. When converting the file to Twinmotion 2026.1, the landscape becomes displaced from it ...

Packaged size of project is double its size when packaging for Shipping Windows (32 bit)

UE - Foundation - Core - Mar 9, 2015

When you package a project in 4.6.1 for Windows (32 bit) shipping, the file size is around 160 MB. When you package a sample project in 4.7.2, the packaged size will be around 345 MB. [Link Remove ...

Crashes when playing Slomo on NiagaraSystem with Solo and DesiredAge.

UE - Niagara - Mar 23, 2023

When Slomo 2 is used to speed up the process, TicksToProcess is greater than 1, which means that ManualTick is called several times during one loop.  When playback is completed by a ManualTick in t ...