Server Editor Window Lag

I’m curious why if I’m following RPC procedures then why when I’m looking at my client1 in the server’s preview editor slightly lags? Meaning if I’m using client 1 (three preview editors up) the client 1 looks fine in client 2’s window but client 1 slightly lags in server preview editor window. To clarify:

playing on server or client = no lag
client 1 in client 2 preview editor window(vice versa)= no lag
server in either client preview editor window= no lag
client 1 or client 2 in server’s preview editor window=slight lag

Any help is much appreciated and thank you!