Chaos sometimes can not generate contact points while two dynamic convex hulls actually collide. It results in instability in the contact behavior​ - such as jittering, inconsistent contact forces, or unexpected collision responses.

UE - Runtime - Simulation - Dec 2, 2025

Context: Chaos Physics is able to use convex hulls to represent object collision geometry for queries and simulation. Problem: Chaos sometimes can not generate contact points while two dynamic conv ...

Cloth jitters in Movie Render Queue renders when temporal sampling is enabled

zComponent - Archive - Dec 6, 2022

The Cloth simulation time step smoothing is interfering with the substepping fix for multi Temporal Samples by changing the very variable DeltaTime and causing some large errors in the cloth simulat ...

Crash when a Deferred Decal (Translucent) base material has a Nanite Override (Masked Surface) Material and the mesh has Nanite + Ray Tracing enabled.

UE - Graphics Features - Ray Tracing - Aug 14, 2025

A crash occurs when Nanite override material instance is used in a project with Ray tracing enabled where: 1 The Material assigned to the static mesh uses Deferred Decal / Translucent and the Nani ...

Gameplay effect modifier tag requirements are not checked for Instant/periodic effects

UE - Gameplay - Gameplay Ability System - Jun 19, 2023

When creating a GameplayEffect, modifiers can tag requirements for the Source and Target tags. For Duration gameplay effects, these tag requirements are checked from FAggregatorMod::UpdateQualifies ...

Bluerpint nativization failed for calling TMap::Find function of a map container with an enum type key

UE - Gameplay - Blueprint - Oct 2, 2020

Followings are nodes in the repro project. [Image Removed] Here's a generated code of the BPvoid ANewBlueprint_C__pf1010915279::bpf__NewFunction_0__pf() { uint8 bpfv__CallFunc_GetInt_NewParam ...

Crash when loading array of UStructs containing Instanced property

UE - Gameplay - Blueprint - Jan 26, 2022

The editor crashes with a failed assertion when opening a blueprint actor that contains a structure with instanced objects. ...

Subobject components do not have undo functionality within the level

Tools - Jan 4, 2021

When moving these components around in the world editor, the transform gizmo will move with the undo, but the actual component will not.  I could not repro this behavior with non-native component ...

Hot reload can prevent code components from being accessible in blueprints

UE - Foundation - Cpp Tools - Hot Reload - Sep 29, 2017

When a class is edited / hot reload preformed, code based components are sometimes removed from the MyBlueprint > Variables section and cannot be dragged from the Components tab into the graph with ...

"Scale for <ComponentName> has a component set to zero, which will result in a bad body instance" warning spam when moving actor instance even with Collision Profile overriden to "NoCollision"

UE - Runtime - Simulation - Jan 12, 2026

When a StaticMeshComponent has a scale component of zero in WorldSpace (after accumulating with the hierarchy from the root to it), function UPrimitiveComponent::OnCreatePhysicsState() logs the warn ...

Visual Logger Timeline is not updated when Viewport is in fullscreen

UE - AI - Debugging - Jan 14, 2025

Context The Visual Logger is a powerful debugging tool to create and record visual representations, and allows people to review the data. Problem The problem is that it does not record things don ...