Unreal Engine Issues
Unreal Engine Issues
Directly opening a modified map asset of a streaming sublevel does not always force it to be reloaded (inconsistent with other map open behaviors)
UE - World Creation - Worldbuilding Tools - Feb 10, 2026When the level currently being edited has unsaved changes and the user opens a new one, the Editor asks if the changes should be saved. If the user answers negatively, the level asset is reverted to ...
Client disconnected due to MissingLevelPackage in editor with Iris and server streaming enabled
UE - World Creation - Worldbuilding Tools - 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 ...
DynamicMaterialParameters Niagara module resets write flags on emitter update
UE - Niagara - Feb 4, 2026When using the DynamicMaterialParameters Niagara module in UE 5.6, 5.7, and UE5-Main (CL 50298778), updating an emitter causes Boolean values, such as Index0Float0Write, to reset to default values, ...
Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine
UE - Anim - Jan 22, 2026Changing the ComponentClass of a ACharacter twice and trying to set a SkeletalMeshAsset crashes the engine with a "Cannot replace existing object of a different class" message. The conditions to re ...
GameplayTagQuery AutoDescription not refreshed after GameplayTag redirect on load
UE - Gameplay - Gameplay Tags - Jan 21, 2026FGameplayTagQuery does not refresh its cached AutoDescription after GameplayTag redirects are applied during asset load. As a result, after renaming a GameplayTag and restarting the editor, the Game ...
Multicast RPCs may be sent to clients in a different level with Replication Graph
UE - Networking - Jan 20, 2026UReplicationGraph::ProcessRemoteFunction does not check if the client has the same loaded world as the server when sending a multicast RPCs. For actors that are persisted partway through a seamless ...
Detaching a component may not be replicated to clients
UE - Networking - Jan 13, 2026Because the archetype for scene/static mesh components has a null value for AttachParent, there are some situations where changes to a replicated component's AttachParent are not replicated to clien ...
Detaching a component with "KeepRelative" location rule can result in incorrect location on client
UE - Networking - Jan 13, 2026When receiving a replicated detachment, USceneComponent::PostRepNotifies will call DetachFromComponent with the KeepWorldTransform detachment rule. If the component is detached on the server with th ...
bWeldSimulatedBodies not replicated with attachment
UE - Simulation - Core - Jan 13, 2026The bWeldSimulatedBodies attachment parameter is not replicated to clients, both in USceneComponent's attachment replication handling and in AActor's FRepAttachment struct. If AttachToComponent is c ...
USceneComponent::AttachToComponent may not be called on client depending on replication order
UE - Networking - Jan 13, 2026If the component being attached is received first, OnRep_AttachParent will set bNetUpdateAttachment to true, so USceneComponent::PostRepNotifies will call AttachToComponent. If the attach parent is ...