When you enter a Server, by Loading and initiating Time any Player or Zombie in Reach can attack your Character, but you are not able to react, until the Game has fully loaded and rendered the Scene. A Player Avatar should be invulnerable until 1 or 2 Seconds after it was moved by the Player her-/himself by Mouse or Keyboard Action at least.

I came across this Issue multiple times yet, not able to defend against a Threat, leaving me intentionally left for Dead or Unconciuosness or bleeding out.