First, it seems like you spawn the actor (master ore) on all clients separately. Is this intended? If master ore actor is replicated, then all clients spawn their own (in Client_Spawn_Ore), and once the server spawns it (also in Client_Spawn_Ore), it too gets replicated to all clients, so all clients have two times a master ore actor (once by manual spawning, another one via replication).
Replicated actors should only be spawned on the server, the server will automatically contact clients to create a replicated version that gets synchronized with the one on the server.
Also, the client should never manually destroy a replicated actor.
Replicated actors should only get manually destroyed on the server. Once destroyed on the server, clients will automatically be notified to remove their replicated version of it.