Unreal Engine Issues
Unreal Engine Issues
WP: Using Make Writable when deleting actors from scene does not delete the actors
UE - Engine Scaling - Streaming - World Partition - Aug 4, 2026When working in a World Partition level using OFPA, trying to use the "Make writable" option instead of checking the asset out will result with the actor coming back to the map after restarting the ...
StreamingGeneration: Actor desc mutator phase now writes ActorDescView directly, breaking the cluster-invariant check in ValidateContainerInstanceDescriptors
UE - Engine Scaling - Streaming - World Partition - May 22, 2026This 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 ...
ServerUpdateLevelVisibility called multiple times from UWorld::AddToWorld/RemoveFromWorld due to child connections
UE - Engine Scaling - Streaming - World Partition - Apr 16, 2026A recent change to ULevelStreaming::ServerUpdateLevelVisibility ensures that this only calls APlayerController::ServerUpdateLevelVisibility once for any non-child connections ( ...
WorldPartitionChangelistValidator incorrectly flags actors referencing the level script actor as invalid
UE - Engine Scaling - Streaming - World Partition - Mar 23, 2026When validating a change list that contains an actor that references the level script in the world (e.g. it has an event bound on the level script graph) it will fail changelist validation 100% of t ...
Client disconnected due to MissingLevelPackage in editor with Iris and server streaming enabled
UE - Engine Scaling - Streaming - World Partition - Feb 9, 2026When connecting to the server, if the client activates some local cells while the connection is still pending, ULevelStreaming::IsConcernedByNetVisibilityTransactionAck will return false. In this ca ...
Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor
UE - Engine Scaling - Streaming - World Partition - Dec 18, 2025Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...
[WorldPartition][CellTransformer] ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack
UE - Engine Scaling - Streaming - World Partition - Dec 17, 2025There is a risk of actor components registering with the wrong world when reconstructed from UWorldPartition::ApplyRuntimeCellsTransformerStack. The repro case is arguably a bad usage, but it was th ...
[WorldPartition][CellTransformer] ISM Cell Transformer breaks component hierarchy when child component are transformed
UE - Engine Scaling - Streaming - World Partition - Dec 15, 2025This case is related to [Link Removed] Closed but is not a duplicate. Please make sure to download the attached project a ...
Orphaned BP actors when using UWorldPartitionBuilder
UE - Engine Scaling - Streaming - World Partition - Nov 21, 2025From an EPS case: --------------------------------- We're seeing a recurring issue where child BP actors are becoming orphaned during any processing that uses UWorldPartitionBuilder. It affects ...
Duplicating OFPA Levels can result asserts when running the WorldPartitionBuilderCommandlet on multiple levels.
UE - Engine Scaling - Streaming - World Partition - Nov 21, 2025The process will assert in UWorldPartition::Initialize on check(!OuterWorld->PersistentLevel->bAlreadyMovedActors); The log from a debugging session (see attached image) that a LevelInstance ge ...