On my time playng on the server, I've observed some bugs like:
1. There might be a bug about "Charger 7", when you use right click to shoot the special laser of this weapon, most of the time the laser goes to absolutely random location, like this is very inaccurate and very frustating, especially because is a pretty good weapon, and the laser, I suppose, should be a special weapon ability that help the player using it, not driving him mad.
2. Sometimes, as a zombie, the crosshair is not visible.
3. Some of the "M-79 Saw off" grenades are not inflicting any damage (I am not talking about the first 1-2 second when a zombie has respawned).