So one if the issues I'm also seeing now (I saw this the first time, but I feel its more noticeable now) is when the zombies spawn, even when the barricades are broken, they aren't moving and are inactive
https://prnt.sc/hx2et6I'm assuming you have their behavior already set to investigative, but I don't usually work with enemies in SP/MP. I think one of the things you can try is have enemies constantly look for player 'A' in region 'B', where in this case region 'B' is in middle of map.
I also notice the barricades aren't infinitely fixable, not sure if by intention or by glitch. I feel it's by glitch because doesn't carpenter autorepair them?
I forget the wave number, but after I saw the red noir limes, there was no more waves coming. I think it was before wave 20, but I cant be for certain. Was it capped for testing, or just a bug that stopped the respawning of zombies?