I’m noob on UE4 replication so i’m not sure if i’m correct, it kind of my guess using my general knowlage. In replication server got the autority it contains master copy of game state which is sent to clients and clients tries to replicate that state. So client need to send command to server by replicated function call or by change replicated varable it should validate it and do it on server then UE4 automaticly replicates that change to other clients. As one of clients is the server change happens there localy and are replicated to other clients, thats why you see change only when you do it on server.