StreamingGeneration: Actor desc mutator phase now writes ActorDescView directly, breaking the cluster-invariant check in ValidateContainerInstanceDescriptors

UE - Engine Scaling - Streaming - World Partition - May 22, 2026

This report is from an EPS case: We hit a regression upgrading our project from 5.7 to 5.8. Map Check (and any other path that ends up calling UWorldPartition::CheckForErrors) assert inside FWorld ...

Orphaned BP actors when using UWorldPartitionBuilder

UE - Engine Scaling - Streaming - World Partition - Nov 21, 2025

From an EPS case: --------------------------------- We're seeing a recurring issue where child BP actors are becoming orphaned during any processing that uses UWorldPartitionBuilder. It affects ...

UWorldPartitionSubsystem::IsStreamingCompleted returning the wrong query result when all cells and actors in location are in DataLayers

UE - Engine Scaling - Streaming - World Partition - Jul 24, 2025

Context: Data Layers is a system within World Partition used to organize Actors both in the Editor and at runtime. It allows for the user to dynamically load and unload layers in the Editor to help ...

Actor corruption due to Hierarchy broken after load

UE - Engine Scaling - Streaming - World Partition - Apr 25, 2023

We recently hit a situation where some actors would suddenly teleport across the map when they were modified in the editor. We figured out that the AttachParent of some actors got reset on editor l ...