Multicast RPCs may be sent to clients in a different level with Replication Graph

UReplicationGraph::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 travel, such as the GameState, if the server calls a multicast RPC on this actor while it is in the destination level and the client is in the transition level, the actor will still be replicated to the client. This can cause issues later, as this actor will be destroyed on the client when going from the transition to the destination level. For example, OnRep_ReplicatedHasBegunPlay may not get called for the client in the destination level.

• In a project using the replication graph, have the GameState send a multicast RPC shortly after initialization.
• On the server, initiate a seamless travel.
• The issue will occur in cases where the server completes the travel before the client. This can be forced by breaking on the client or otherwise stopping the process.
• Observe that the client will receive a net update for the GameState while it is still in the transition level.