A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction

UE - Simulation - Gameplay - Dec 16, 2025

Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...

Movie playback doesn't work on Mac and iOS the way it did before

Tools - Aug 5, 2016

New media framework is making Mac/iOS not render ...

ZenGarden or project with MSAA enabled crashes on iPhone 6 and 6+

UE - Platform - Mobile - Jul 19, 2017

Zen Garden crashes on the iPhone 6+ before anything appears onscreen. Occurred on: iPhone 6+ on 10.3.2 Didn't occur on: iPhone 6S on 10.3.2 ...

Race condition in full builds of UE4 engine source

UE - Foundation - Cpp Tools - UnrealBuildTool - Sep 26, 2019

This is a race condition caused by how "Clean.bat", a batch file used during rebuilds, tries to manually rebuild the UnrealBuildTool project when it runs. This causes a spam of UnrealBuildTool build ...

Culling Distances Not Working For Static Mesh in Procedural Content Generation Tool and Foliage Tool

UE - World Creation - Procedural Tools - Mar 28, 2025

When creating Foliage or Procedurally Generated Content the culling settings of the Static Meshes do not apply correctly. As soon as either a minimum or maximum cull distance is set the Static Meshe ...

In editor, sub level instance's streaming state persists incorrectly after toggling Level Behavior without saving

UE - World Creation - Worldbuilding Tools - Level Instances - Jun 11, 2025

When adding a sub level with world partition streaming to a main level where the streaming is also enabled, setting* Level Behavior* of the sub level to Standalone, and saving the result, in the fir ...

Hot Reload does not update blueprint pins

UE - Gameplay - Blueprint - Jan 15, 2015

When changing the variable type or return type of a function in code and hot reload in the editor, blueprints that use the variable/function do not have their pins updated until the editor is closed ...

iOS Shipping Build using std::thread crashes on launch

UE - Platform - Mobile - Jun 2, 2017

A user is reporting that using the following code in a GameMode class causes shipping iOS packages to crash on launch:void ANOGSSDKGameModeBase::StartPlay() { std::thread([](){ std::clog << "THRE ...

Classes in TargetDenyList modules are still referenced from Components on BlueprintGeneratedClasses and cause runtime warnings

UE - Foundation - Feb 25, 2024

Other than the presence of the error and the performance cost of looking for a package on disk that does not exist, there are no behavioral problems. When running with legacy (non-iostore) pakfiles ...

AddComponent node fails to be scheduled after adding an "expose on spawn" variable to an ActorComponent-based Blueprint Class.

UE - Gameplay - Blueprint - Nov 13, 2015

If an existing AddComponent node is placed in an Actor Blueprint's Event Graph for a custom ActorComponent-based Blueprint Class, the node will fail to be scheduled after adding a variable marked "E ...