Halo 4 Matchmaking Team Division

I was wondering if anyone knew how this game divvies up teams. I like to play Capture the Flag, but it becomes increasingly hard to play with a deficit of teammates. I’ve been in a game where players were found (let’s say 8) and it splits the teams 5 and 3. How does this happen? Why does this happen? Who allows this to occur? Are there any patterns or tell-tale signs the game has for this occurrence so I can better avoid it?

C’mon, guys. Anyone?