Motion vectors not generating correctly in build

UE - Simulation - Physics - Nov 3, 2023

Also tried using “show VisualizeTemporalUpscaler” and noticed the frames that have missing motion vector data showed up as pops in the “show VisualizeReprojection” part of the visualizer. ...

Map actor reconstruction does not reattach external non-root components

UE - Framework - Components - Jan 17, 2024

For two map placed actors, if one actor B's non root component is attached to another actor A, the attachment is not retained when actor A reruns its construction script, such as when moving actor A ...

Using "Change Class" on Spawnables, Possessable references retain old Class info

UE - Anim - Sequencer - Apr 22, 2024

Changing Class for Spawnable objects in Level Sequence did not have any impact on Possesable objects in Subsequence. It's still referencing the previous Class. Also found in Release-5.4, CL: 329753 ...

When importing static mesh using interchange and collision is generated, the asset does not have Collision Generated set to true

UE - Editor - Content Pipeline - Import and Export - May 19, 2025

Context: The Interchange Framework is Unreal Engine's import and export framework. When importing a mesh without collision, collision can be auto-generated. Problem: The problem is when importing s ...

Water tiles flicker in and out of visibility with instanced stereo enabled.

UE - Graphics Features - Jun 16, 2025

Water tiles flicker in and out of visibility when playing in VR with instanced stereo enabled. Requires instanced stereo rendering to be enabled (does not require forward shading to be enabled) Must ...

Lumen reflections break when the normals don't match the pixel depth information.

UE - Graphics Features - Lumen - Oct 23, 2025

Lumen Reflections can leave black spots in chrome materials with strong normals. Also tested on UE 5.5, CL: 41545209 and UE 5.6, CL: 45232827 ...

Adding to Struct causes 'Inappropriate Outermost' warnings

UE - Gameplay - Blueprint - Jun 2, 2015

Adding to Struct causes 'Inappropriate Outermost' warnings to be spammed to the Output Log ...

If PIE is paused using the 'Pause key', the Pause or Resume buttons on the toolbar will no longer start PIE

Tools - Feb 5, 2015

If PIE is paused using the 'Pause key', the Pause or Resume buttons on the toolbar will no longer start PIE. You have to make sure that the icon is toggled to Pause, select the viewport, and then p ...

Editing static functions in Blueprint Function Libraries with hotreload can cause saving issues with blueprints calling them

UE - Gameplay - Blueprint - Sep 26, 2016

When editing a Static function from a Blueprint Function Library, any blueprints that have already had it added are unable to be saved. This can be worked around by removing the node and adding it a ...

Changing code based component category causes component to become ineditable in blueprints

UE - Gameplay - Blueprint - Mar 27, 2015

When a component written in code has it's category setting changed in blueprint the rest of the details for that component will not be editable once the component is deselected and reselected. ...