Heya, what platform are you on and were you in the same lobby the whole time? It will generally try to match you up with those lobbies first (the ones with all maps including the map packs), but if it can't find any applicable lobbies it will then try to place you in a full low ping lobby.
Also, does it show those new maps in the available maps when you hover on a playlist in the MP menu?
I’m on Xbox. Tried many different lobbies. Yes they show as available.
Yes, I can access in custom games. And ya it is the newest map pack.