[danielsumi]

From what i observed:

It turns all cheat-flagged cvars to default values after someone joins the server trough console or server browser and them leave it.

When the server see that no one is in-game anymore, the hibernation mode takes over and it revert the map to the beginning, and also set the cvars to default values.

As i said, its not such a big deal because it seems that whenever players join trough lobby system (the main system to join a game in l4d), the server is forced to change the map before players join the game, so all the settings are... uh... set to whatever values are listed on your /mapconfig/ folder.