Trivia: Catherine tosses a huge black gorilla to Tess as she gets off the helicopter. This was an inside joke reference to "Gorillas in the Mist" which Sigourney Weaver had just finished filming and was released only three months before this movie.
Trivia: You can see a quick cameo by Ricki Lake in the wedding reception dance scene. She is the bridesmaid that Jack asks for information about nicknames for the girl that is dancing with Trask at the time.
Trivia: A then unknown Kevin Spacey has a cameo early in the film. He plays Bob Speck-the guy that Tess has an "interview" with in the limo. This is also one of the last films that you can see his large cheek mole in. He had it removed between See No Evil, Hear No Evil and Dad. Now all that remains is a small scar that can be seen when caught in the proper lighting.
Trivia: Look for a very young David Duchovny making his movie debut. He is one of Tess' surprise birthday party friends in the far left hand side of the closet.
Answer: It is also stated in the movie that Katherine just transferred down from Boston, and she is staying at her parents house. She also mentions in another scene that her and Jack are now in the same city. Plus Tess helps plan her welcome party to get to know others in her department indicating that she is new there. Maybe Jack had not got a chance to visit her office yet, which would explain why he would not have known.