[AI] Debug Render Scene Proxy hits ensure for registering a delegate twice during level streaming.

UE - AI - Debugging - Aug 31, 2022

Description from licensee: We're seeing an ensure get tripped up in FDebugRenderSceneProxy that says "DrawDelegate is already Registered!". Debugging the issue, we have confirmed that the DrawDeleg ...

Merging Splines causes Engine to Crash in 5.1

UE - World Creation - Worldbuilding Tools - Merge Actor - Dec 15, 2022

Attempting to merge two spline actors causes the Engine to crash. This issue occurs with the Steps to Reproduce regardless if there are more branches added to the tree branch spline/enabled, and reg ...

Interchange framework is bypassed on the second attempt after a failed import

UE - Editor - Content Pipeline - Import and Export - Jul 14, 2025

Hello! We have encountered a bug with the Interchange pipeline. When an interchange texture import is cancelled due to non-power of 2, and then the same texture is imported again without any change ...

Chaos : Rigid body sleeps when very small external force is applied by AddForce

UE - Runtime - Simulation - May 25, 2022

When a small external force is applied to the rigid body, the VSmooth value is reset in the ResetVSmoothFromForces function. Since this function ignores the current velocity, a very small velocity ...

Pressing the "Show Inactive" button in the material instance editor did not display groups that did not contain the active parameter

UE - Rendering - Architecture - Materials - Aug 1, 2024

When pressing the "Show Inactive" button in the material instance editor, all material parameters are supposed to be displayed in the EditorUI. This is not the case, only some of the parameters are ...

Asset returns after being deleted from the content folder while the editor is open

UE - Editor - Content Pipeline - Content Browser - May 8, 2017

Asset returns after being deleted from the content folder while the editor is open. A deleted asset comes back and does not prompt to save it. This leads to the asset being removed when the editor i ...

[CrashReport] Assertion failed: !PinRef->bWasTrashed | UEdGraphPin::SerializePin()

UE - Gameplay - Blueprint - Aug 29, 2017

This is a common and longstanding crash that has occurred since at least 4.15 and affected nearly 500 users. The CrashGroup was previously linked to [Link Removed], but that had specific repro step ...

Typo in "BaseEditorSettings.ini": under section [/Script/UnrealEd.ContentBrowserSettings], key "DisplayPluginFolder" (singular) should read "DisplayPluginFolders" (plural).

UE - Editor - Oct 11, 2025

File "<ENGINE_PATH>/Engine/Config/BaseEditorSettings.ini" contains the following setting: [/Script/UnrealEd.ContentBrowserSettings] ; Whether to display the game project plugins in the Content Brow ...

Niagara Simulation Stage + DynamicMaterialParameters crash

UE - Niagara - Feb 6, 2021

deleting the code "&& SimulationStages[i]->bEnabled" in UNiagaraEmitter::GetScripts will bypass the problem [Image Removed] ...

Viewport Controller Camera Control Regressions in UE5.8

UE - Editor - Jul 16, 2026

In UE5.8 it appears some changes were made to the camera control and navigation in the editor viewports. You can no longer use controller and mouse simultaneously to control the camera. Previously ...