Hi,
For player controlled characters, it is expected for the frequency that the server replicates movement data to simulated proxies to be dependent on the frequency that the owning client is sending movement RPCs. A dedicated server will only move a character once it receives a move from the owning client, before it then replicates this movement to simulated proxies.
On the client, these simulated proxies are ticked at a constant rate, with sim proxies using smoothing/interpolation to make movement appear more fluid between these updates from the server.
Thanks,
Alex