My friends can't exactly play the MCC properly

What I mean by that is…that…in matchmaking alone they do fine, but we can’t play anything together, and in the rare chance we do get to play together it’s always laggy or buggy (Like in custom games recently, one of them got kicked out of the game once the game started) for them. They have Time warner cable as their ISP, could that be the problem? It seems to only happen with halo and occasionally GTA V…