Been seeing a lot asking about this issue so for all those are a having the "issue" of the common/special infected not moving or attcking, here is how you fix it:

1) Open your spawn menu
2) Find the VJ tab on the right side panel (not top!)
3) Open the AI option
4a) Make sure this setting is not enabled: "VJ Base Friendly"
4b) Make sure "Chase Enemies" is on
If you still are having issues try turning off "Wander", also make sure you map has a navmesh, quickest way to check is just spawning a sanic type nextbot

Hope it helped