Well, each DLC map pack has it's own unique percentage (%) of showing up in matchmaking. The percentages and which map pack that is "highlighted" for the time period differentiates. As long as you have the maps in Custom Game and are able to play them, you're okay.
I rarely play on the desired DLC maps I want to in Matchmaking. You simply have to just get lucky when in there looking for that one map you want to play on.
• [SUPPORT] Co-Op Treasure Changes [54 Kudos][21 Possible Changes] •
• Crushing+ • No Incentive to playing Co-Op Arena (my ideas to fix that) •
• A Co-Op Dream Map • Deadly Drive - Chapter 2.5 - Co-Op Adventure •
• Pinkerton's Mansion - Co-Op Arena Map • *-=JD--'s Ultimate Co-Op Guide=-* •
• Co-Op Mods for other Weapons • Co-Op Kickback Fixes - My ideas •
• "A Forced Collaboration" - Drake, Eddy, and Flynn •