Same issue. I had a steam update for PZ and run the 32-bit version, after steam updated my game last night the zombie spawns where abysmal. As in I went through muldraugh shooting a shotgun and only pulled 1 zombie in the entire town. Same issue in rosewood. Was playing with filibusters used car mods thought it may have been the issue but reinstalling and starting a completely new file did not help either. Hopefully can get back to slaying some zomboids soon! Side note: I LOVE THIS FREAKING GAME!