Apex Destruction - Destructible Mesh disappears after Fracture

UE - Simulation - Physics - Destruction - Jan 3, 2020

Fracturing a mesh with Apex Destruction in 4.24.1 (CL-10757647) causes the mesh to disappear after clicking Fracture. This behavior was not present in 4.23.1 (CL-9631420). Unable to confirm this in ...

Crash when generating mip maps for texture

UE - Graphics Features - Dec 23, 2019

Generating mip maps results in crash and seems to duplicated 1x1 mip level. NOTE: The bug was originally reported in 4.23.1, however, for some reason I was able to open the texture in 4.23.1 afte ...

NaN is handled differently when clamped on Windows and Android/iOS

UE - Platform - Mobile - Oct 18, 2017

NaN (Not a Number) is handled different when clamped on Windows and Android/iOS. If you clamp a NaN (Acheived by -3 ^ 0.2 in the reproduction project) from 0.0 to 1.0 and then print the result, you' ...

Regression: FAnimInstanceProxy memory leak when BeginDestroy() called on UAnimInstance before USkeletalMeshComponent

UE - Anim - Runtime - Feb 10, 2025

In UE 5.5, the fix applied by CL 36529858 in ue5-main updated USkeletalMeshComponent::ClearAnimScriptInstance() to call AnimScriptInstance::UninitializeAnimation() on the animation instance. This, i ...

Split-screen players not rendering

UE - Graphics Features - Feb 11, 2015

When using the Create Player node to setup split-screen multiplayer, only the last player created will show properly. All other players experience render issues for their character and environment. ...

Artifacts in imported GLB and GLTF files

TM - Interoperability - Mar 10, 2025

Reported in SF [Link Removed] Client reports that many of their GLB and GLTF files they use appear with visual artifacts when imported to Twinmotion. These artifacts only appear in Twinmotion and n ...

Inconsistent events triggered by FlushProcessedKeys during keyboard hold input

UE - Gameplay - Input - Dec 20, 2024

Key repeats from the OS do not affect the EnhancedInput normally, but it causes inconsistent event triggers when FlushProcessedKeys is called with holding a keyboard key down. Removing references t ...

Access violation - code c0000005 (first/second chance not available)

UE - Foundation - Core - Feb 4, 2015

Crash Reporter: [Link Removed] Opening a project created in 4.6.1 with 4.7 built from GitHub branch 20150203 (last commit: 5bac1375be31053932c7b9123cc3bb94c70dd5e0) results in crash. ...

Lighting build fail due to failing to open channel for material data

UE - Graphics Features - Apr 21, 2017

Licensee reports lighting build fails for their specific levels which were created in 4.14.1 then moved to 4.15.1. Workaround: Setting LogLightmassSolver verbose level to Warning can show "Warning ...

Widgets With Retainer Boxes Are Selected When Behind Widgets Without One

UE - Editor - UI Systems - Dec 24, 2019

When a widget that has a retainer box is behind another widget that doesn't have one it will call it's onclick instead of the one in front of it in the UMG when clicked (see attached gif). This beh ...