I know this is almost 10 years later, but I thought I would mention this in case anyone is looking back on this question now.
(This information comes from experience with UE4 and UE5, it may change in the future)
If you are testing your game from within the editor (PIE or clients in separate windows), it will always show on all of the client windows that open. For this reason, you may also see something print to screen 2+ times when you only call it once.
If you instead package the game and then test it, you should see that it only prints on the one client you are trying to print it on and it only prints one time, assuming you are calling it properly.