Check initial replication completed

I have an moving Actor who walkes along a Pathway instance. The game has to handle lots of players, so the server shouldn’t replicate the new position every tick. Instead the clients calculate the position themselve. Therfore I set all the necessary data as replicated and implemented a NetMulticast function that is called on the server after the spawning to tell the clients to start moving.

But it seems that this function call arrives earlier than the replicated data, which is still NULL. Can I check for initial replication completion somehow?