Same thing yesterday at NY8. I have found myself in camo on first view and invisible on 3rd person view and for others. Zombies don't see me and nobody hear my shooting (but weapon is lethal). I don't need eating and drinking and had problem with "pistol" slots: if I try to take some ammo fo pistol - half of active inventory is dropping on a ground. Also my invisible body doesn't start spawn. I can be visible only for a second during re-loading weapon. It was funny bug then I protected other survivors by killing angry zombies in Chernogorsk like a ghost. :)