Instanced static meshes fire an erroneous performance assert about loose parameters.

UE - Graphics Features - Sep 4, 2019

 "This ensure is intended to catch regressions where rendering programmers add a loose parameter to LocalVertexFactory, breaking dynamic instancing on regular static meshes.  InstancedStaticMeshes c ...

BP timelines: when converting internal curve to external, the external curve isn't used until BP is recompiled

UE - Framework - Blueprint Editor - Aug 28, 2023

Blueprint timelines: when converting an internal curve to an external curve asset, the curve asset's data isn't used until the blueprint is recompiled. This is confusing as there is no indication th ...

'GetClassDefaults' Can Cause Blueprint To Become Modified When Unrelated Blueprint Is Compiled

UE - Gameplay - Blueprint - Sep 22, 2023

The stems from a really old change (CL 2948683) to fix [Link Removed]. Compiling ObjectA will call RefreshExternalBlueprintDependencyNodes on its dependent BP,  ObjectB_ReferencesA, which reconstru ...

Substrate Unlit editor view mode renders black with Blendable GBuffer

UE - Rendering - Features - Shading Models - Mar 18, 2026

When using Substrate materials with SUBSTRATE_GBUFFER_FORMAT==0 (Blendable GBuffer), the Unlit editor view mode renders completely black. TopLayerData.UnlitViewBaseColor is never populated in the bl ...

XAudio2 DestroyVoice call causes significant hitching on some architectures

UE - Audio - Aug 10, 2015

Another thread: https://answers.unrealengine.com/questions/241358/amd-cpu-very-low-performance-because-ixaudio2sourc.html Note: This not a regression and has existed since our first implementation ...

Adding ProceduralMeshComponent Class to a project prevents the code from compiling

UE - Gameplay - Aug 5, 2016

After adding a classed based on ProceduralMeshComponent the code for the project does not compile any longer. **This is a Regression - Adding ProceduralMeshComponent class would compile successfull ...

Scrollbars bounce back when scrolling with the mouse wheel

Tools - Aug 8, 2016

Multiple scrollbars throughout the editor bounce back when the user scrolls with the mouse wheel. The effect looks like the scrollbar is rubber banding when scrolled. This issue has been found wi ...

Crash occurs when using Random Node and Branch within Sound Cue

UE - Audio - Aug 22, 2016

A crash occurs when playing a Sound Cue with Random node used in conjunction with a Branch node. In the original report the user specifically mentions the crash does not occur if you have not opene ...

User created widgets from widgets that are normally not focusable appear to break navigation when added to another widget even when focusable set to true

UE - Editor - UI Systems - Oct 28, 2016

User created widgets from widgets that are normally not focusable appear to break navigation when added to another widget even when focusable set to true Example: A widget with only a text block in ...

Using Show Mouse Cursor and Ejecting Prevents Actors from Being Moved

Tools - Mar 31, 2016

When you have the mouse cursor set to show in game, if you use shift+f1 to unlock the mouse, eject, and then attempt to click and move an actor using the transform gizmo, you are unable to do so. S ...