I read all posts on the first 6 pages, so I'm not sure if anyone has had the problem I have. My friend and I were scoping out the NE (Krasnostav) Airstrip, and while he was way in the distance prepared to save me from whatever danger, I sneaked my way up to the communications tower. I noticed while climbing the ladder to the top, my visibility went all the way up to 5 bars, which I found to be a bit ridiculous. Anyway, after I had checked out the loot inside, I was making my way out the front door, while crouch-walking (which I only consider crouch-walking to be the slowest version of mobility while crouched) and somehow attracted 2 walkers on the opposite side of the building. There was no possible way for them to detect me from noise, so they had to have seen me through the walls. I went back inside to kill them, and of course had to deal with a few more after that. Once I had killed them all, I started walking out again, when 2 infected (a walker and hopper) literally popped out of the wall and started attacking me. I did hear them before, but I simply figured that they were on the other side of the building. Since then, while looting cities such as Berezino (which, by the way, I can still sneak through, as long as I stay prone the entire time), I've been afraid to go near the entrance of buildings because I feel like infected will pop out of the walls again. I suspect this has to do with the new fix of infected not spawning in buildings, since it did not ever happen before 1.7.1. And while infected popping out of building walls to attack me has happened, I have not yet encountered any zombie spawns inside the actual building (the parts a player is capable of being in). I hope this can be fixed soon, because I hardly want to go inside a building anymore if I hear any zombies near the building.