Valve has pushed out a patch to fix a few bugs and exploits that were introduced in the Survival Pack download. Most notably, the patch addresses exploits on several Survival mode maps, so we shouldn't see anymore 10 hour + times being posted to the leaderboards. Hit the jump for the full list.

• Darkened the Lighthouse background movie and increased the contrast with the user interface elements
• Chapter selection is now available when creating a Survival lobby
• Single player coop now works correctly after playing Survival online
• The correct game mode will be set when playing back a demo
• Changed holdout server spew to be development only
• Stats are no longer updated while viewing a demo
• Correctly update the leaderboard based on the player's personal time, not the team best time
• Show the player's best time in the scoreboard
• Removed Survival exploits from The Terminal, Last Stand, The Crane, The Boathouse and The Warehouse
• Fixed tanks sometimes not spawning after 15-20 minutes

UPDATE: This hasn't hit the Xbox 360 yet. PC only for now.