Network Emulation outgoing dropped packets on client higher than expected

UE - Networking - Oct 14, 2022

Under certain network emulation settings, it looks like outgoing packets from the client will be dropped in groups (around 4 or more packets at a time) rather than individually. This leads to the ac ...

Reliable Multicast RPC may be called before BeginPlay for character on client

UE - Networking - Sep 28, 2022

Related to [Link Removed], where calling a multicast RPC in BeginPlay results in the character being spawned on the client with the incorrect role/initial property data. One thing to note: this does ...

Push based fast array with net.PushModelSkipUndirtiedFastArrays not replicating across multiple PIE sessions

UE - Networking - Sep 19, 2022

The conditions for this bug are fairly specific. The actor must be statically placed, with its only replicated property being the fast array, and net.PushModelSkipUndirtiedFastArrays must be enabled ...

Client may receive failure message before ClientTravel RPC during non-seamless travel

UE - Networking - Aug 9, 2022

See linked UDN for more info. When a server initiates a non-seamless travel, it will inform any connected clients by sending the reliable ClientTravelInternal RPC. After a delay (controlled by Serve ...

Changes to AActor::SetReplicates caused Role/RemoteRole replication fix to regress

UE - Networking - Jul 14, 2022

There was a recent bug report that matched the description of some older cases (see linked UDN). The issue raised in those cases, [Link Removed], had been fixed, but the recent question seemed to in ...

Ensure hit in OutdatedKnownStaticMeshDetected for replicated StaticMeshComponent

UE - Networking - Jun 10, 2022

The component's KnownStaticMesh value is updated whenever UStaticMeshComponent::UpdateBounds is called, and AActor::OnRep_ReplicatedMovement can result in this being called for the component. If thi ...

Push based, COND_InitialOnly property can fail to be replicated when actor becomes relevant again

UE - Networking - Jun 9, 2022

COND_InitialOnly properties can be resent when an actor becomes relevant to a client again. However, if the property is push based and it was never replicated the first time the actor was created on ...

Replicated subobject won't be recorded in replay checkpoints if it has no replicated properties

UE - Networking - Jun 8, 2022

Because the subobject's RepLayout is empty, it won't write anything to the bunch when recording a replay checkpoint. This means that when scrubbing to a time past a checkpoint, the destroyed subobje ...

Pawn's role is incorrect in BeginPlay on client if a multicast RPC is called in BeginPlay on server

UE - Networking - Jun 6, 2022

It seems as though calling a multicast RPC during BeginPlay on the server will cause the new actor to finish spawning on the client before applying any initial replicated data, such as the actor's R ...

DemoNetDriver can cause ClearVoicePackets to be called multiple times in one tick

UE - Networking - May 18, 2022

Because DemoNetDriver doesn't override PostTickFlush, it will call the base UNetDriver's PostTickFlush. When both the game NetDriver and DemoNetDriver are ticked, this results in the online interfac ...