The Hunter Association is a big organization that has excellent internal cohesion between its departments. That is to say, only highly confidential information could be successfully kept a secret within its walls.
The war between the Cardinal's assassin and Shen Yuan isn't exactly a state secret, plus the fact that Chairman Mao spoke highly about it during the press conference. It didn't take long before the minor details of the incident became well-known among the Hunter Association's agents.
