Zombies in the game can possibly crash the game during a conflict with the timing of AI behavioral commands. Player will become detected, and a conflict results likely from Zombies attempting to path find toward players, or as a result of duplicate, or conflict commands. Experienced this on all WD servers on DayZ 1.04 release; typically happens in military bases where zombie population instantly makes server crash fatal for the player once they re-log in.
Is this reproducible?
Yes. It seems to happen precisely while and when looting/navigating certain military buildings, and the prerequisite is that a zombie has to either spawn in locally and see you, or detect you, and attempt to path find to your location.