Open Formats: Interchange Import PIE - Importing static mesh while a PIE session is running permanently breaks nanite on the asset

UE - Editor - Open File Formats - Mar 12, 2025

Importing a Static Mesh during PIE can cause it to never enable Nanite, even if it reports that Nanite is enabled. To re-enable Nanite on the mesh, the asset needs to be deleted and imported again ...

Blackboard decorator node does not abort lower-priority nodes

UE - AI - Feb 16, 2026

When a branch of a selector is deactivated, all auxiliary nodes and observer delegates are removed. If the branch is reactivated soon and the CurrentActiveNode remains unchanged, the behavior tree l ...

Cannot Increment a Blackboard Key Value

UE - Gameplay - Blueprint - Feb 4, 2016

Getting a blackboard value as int and then attempting to increment it does not actually increment the value. Upon attempting to increment a value that started at 0, the editor continued to print out ...

Closing a Geometry's Collection Dataflow Editor window when the ChaosVehiclePlugin is enabled is crashing the Unreal Editor when running it with the -stompmalloc flag

UE - Simulation - Core - Jan 27, 2025

As the title describes, closing a Geometry's Collection Dataflow Editor window when the ChaosVehiclePlugin is enabled is crashing the Unreal Editor when it is running with the -stompmalloc flag. The ...

Hot reload causes AnimBlueprint to lose functionality and crash

OLD - Anim - Mar 31, 2015

Casting to a character class inside of AnimBlueprint after a hot reload caused editor to crash Crash Reporter: [Link Removed] Additionally, Casts fail, breaking AnimBlueprint after a hot reload ...

Overlapping isn't updated on replicated components after SetWorldTransform

UE - Networking - Dec 10, 2015

Overlapping isn't updated on replicated components after SetWorldTransform. Updating the transform on the Actor itself updates the overlapping as expected. Reproduced in 4.10 and Main (CL# 2798114) ...

iOS Metal-based build crashes at launch with sub-levels.

Tools - May 16, 2016

Application crashes when deploying a game to iOS with Metal enabled. This has only been reproduced if a sub-level has been added to the starting level within the project. This seems to only happen ...

Crash closing a project that was packaged on Windows for Linux

Tools - May 11, 2017

This occurred with both Development and DebugGame build configurations. In the game's console I tried both "quit" and "exit" and reproed the crash. The crash also occurs via Alt + F4 or closing vi ...

Resetting material instance parameters to default value does not update the appearance of the object that the material is applied to

UE - Rendering - Architecture - Materials - Mar 10, 2025

When a material instance with exposed parameters is applied to a landscape; the parameters set to a new value and then reset to back the default value, the landscape does not respect the new default ...

Crashes when attempting to use an Instanced Struct inside Control Rig / Rig VM

UE - Anim - Rigging - Control Rig - Mar 17, 2025

Currently, the Control Rig Editor allows the user to use the "Instanced Struct" type, for example for a variable or function input/output. However, this type does not seem to be properly supported ( ...