When playing on 2 monitors, if I click to a window on the 2nd screen (AKA Minecraft losing focus) Minecraft minimizes and I get disconnected from any server I would have been connected to. It tells other players that I have left but my game does not update until 10-15 seconds after Minecraft gets focus back and then it notifies me that I have been disconnected from the server. This happens regardless of being connected to a player's world or a Realm.