There is a zombie with a black texture and it only appears on its actual model not in inspect.
Pictures are below:
http://i.imgur.com/Dxn6AjQ.jpg - not sure if you can see but it is black.
http://i.imgur.com/Gyb51OQ.png - this is the zombie after inspecting.
Join .62 experimental
Hello DannyDog and thank you for the report.
This is an issue we are aware of and it has been scheduled for a fix.
The issue has been fixed internally and should be fixed on Steam soon.