Halo 3 Stat Tracking

It appears, in my limited observation, that Halo 3 games add neither kills or deaths to overall career record in game. Why is this? It appears all others count, and, due to the very nature of my personality, I tend to shy away from Halo 3 games if they do not continue progression, even if it is my favorite of the collection. I hope this wasn’t intentional.

Could just be a loading error, all my game time was laggy and finally just added up a few days ago.

You are correct. Halo 3 stats do not load to your viewable service record on the game, but they are recorded towards your overall stats on the website. Just another glitch/fail by 343