Lag in Custom Games

So, yesterday I took some time to go into a custom game to get some pictures of my spartan for a cool background. All was well…that is until I started rubber banding all over he place! Are you serious? I cant play a solo game with no other players without lag?? Now, before you dismiss this as a little kid with an awful connection, I’m running 75mbps at all times and I’m the only one in my apartment that uses the internet. Plus I’m on a wired connection. I get that dedicated servers are “better” but this is just sad. I love Halo 5 and i think that it is well made and that the matchmaking system is second to none. I’m just disappointed.