Broken zombie movement due to the 'high loot = high zombies' feature?

Im at the massive gunstore near echo creek and the steel factory and ive ran into an extremely weird problem every time i try to loot the main room. ill clear it out of all the zombies way out of hearing range of outside zombies, loot about one cabinet, and then outside zombies will immediately come inside through the windows or other rooms unalerted. This happens every. single. time. But i havent alerted a single one, they just automatically enter the room, and i think thats because of something to do with the new zombie distribution system. Anyone else had similar experiences?