Stats not working?

This is a minor problem compared to others, but it’s very annoying. So I was playing the infection playlist and decided to run a test, I completed a match on halo 2A with about 20 kills and 5 deaths. When checking my career, it only registered 3 kills and that’s all. After that I had a horrible game in halo 3 which was laggy and finished with 1 kill and 4 deaths. This game saved perfectly in my career and added the kills/ deaths which was quite annoying as the other match hadn’t loaded. Is anyone else experiencing this problem? Also medals are not working to well for me either.