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 ...

When duplicating multiple actors with alt+drag, Translation/Rotation widget goes to incorrect coordinate space

UE - Editor - Mar 4, 2024

Note: This bug has been observed in all tested engine versions, from UE 4.24 to UE 5.3 and in ue-main. When shift+selecting multiple actors in the Level Editor, the currently-active transformation ...

[CrashReport] UE4Editor_Engine!LoadSpecialMaterial() [unrealengine.cpp:1523]

UE - Graphics Features - Nov 10, 2017

This is a longstanding crash that has occurred for more than 200 users since at least 4.13. Based on user descriptions this appears to permanently corrupt a project. User DescriptionsI just turned ...

[Metal-Epic:Tools] Compiling Metal 2.0 shaders on XCode 9.3 beta with desktop forward selected fails on iOS

UE - Graphics Features - Mar 30, 2018

Shaders fail to compile with a series of cube map errors (subset below): LogShaderCompilers: Warning: 17 Shader compiler errors compiling global shaders for platform SF_METAL_MRT:   LogShaderComp ...

Half precision is not supported for OpenGL ES 3.1 Pixel Shaders

UE - Platform - Mobile - Apr 6, 2018

Fix the cross compiler so half precision is supportedAdd a project setting to specify the default precision to support on ES31. Be sure the shader version takes this setting into account. — User des ...

UPrimitiveComponent mouse events when underneath Slate widgets not correct

UE - Editor - UI Systems - Slate - Jan 7, 2016

Licensee is adding a widget to the viewport overlay via AddViewportWidgetContent(). The widget receives mouse input when hovered. They return unhandled from all their widget's onmouse functions and ...

FTabManager::FindPotentiallyClosedTab Crash Due to Invalid Array Indexing

UE - Editor - May 25, 2023

As you can see from the above callstack it appears that calling RestoreArea can call FindPotentiallyClosedTab again higher in the stack, which can Remove() an entry from CollapsedDockAreas- this cau ...

SteamVR turns off vsync globally

UE - Platform - XR - Feb 21, 2020

Additional Info From User: Result: Vsync will get turned off by FSteamVRHMD::Startup() setting a global console variable, regardless of your project configuration. Expected: Vsync is only deacti ...

Mover Plugin: UNavMoverComponent::GetFeetLocationBased() returns incorrect FBasedPosition when using WalkingMode over a Movable floor, making UPathFollowingComponent erroneously detect a blocked move

UE - Runtime - Character - Nov 12, 2025

Function UNavMoverComponent::GetFeetLocationBased() on file "NavMoverComponent.cpp" returns an FBasedPosition built from an FRelativeBaseInfo. The "MovementBaseInfo" is read from key "CommonBlackboa ...

CommonUI: FUITag, FUIActionTag variables can't connect with blueprint wildcard Equals node

UE - AI Workflows - UI Systems - Jan 5, 2026

Context UITag and UIActionTag are blueprint-exposed struct classes that derive from GameplayTag. GameplayTag variables can be compared in blueprint with ==. Under the hood, the node maps to  UBlue ...