There seems to be a bug in the IWBUMS vehicle build where there is a invisible zombie in that shows up every now and then when we are fighting off big herds. We manage to take out most of the herd but then one of us ends up getting scratched by a non existent zombie/invisible zombie. Both players see NO zombie at all and when we walk into or swing our weapons in a certain spot, we get bitten/scratched by a zombie. I'm hosting LAN Gameplay via steam for my brother and I. Is this a known bug and is there anyway to avoid this? It seems to happen a lot when we kill off a lot of zombies that are being attracted to cars. This is really annoying because we don't want to die to something that can't be avoided and turning off infection makes the game too easy.