It’s because Punkbuster isn’t connected to the internet when you are vieinwg the active connections.
PB is most often just running a background service, Punkbuster.EXE that verifies your content with the game server you are playing. (To make sure you don’t have any modified or extra files etc) after that Punkbuster will continue to stay connected to the game server while you are playing, Listening, and waiting if the host request a screen shot, etc.
Try playing your loading your game, Press ALT TAB to switch to windows and open Comodo’s Active network.