PC patch 4 has been uploaded to Valve, and this is now available via Steam.
Patch notes are as follows;
• Fix for a Skybox rendering problem in D3D11 build on Nvidia Fermi cards
• Various small D3D11 optimisations
• Fixed rare bug where clients would get stuck on the loading screen.
• Fix clients not seeing the 'custom match' flag updating in the 'Browse' screen when the dedicated server was changing settings after initially hosting a match without changing any variables
• Use an [R] prefix for rcon command output text upon successful receipt of a rcon command
• Prevent windows cursor being stolen when starting in windowed mode but then doing ALT-TAB immediately.
• Show (and sort) dedicated server search results as they come in instead of waiting for search to complete before displaying anything.
• Fix extraneous [Team] appended to MOTD text when joining game in progress
• Invitations to dedicated server games now work.
• Fixed all dedicated server games showing as "at lobby" in the server browser, regardless of being at lobby or in progress.
• Fixed "Ghost players" being created on a server if the Steam backend could not be reached for authentication when someone connected. These appeared in the player counts when browsing servers, and in the server details player list when viewing servers in the Steam client server list.
• Added more info to server console when players connect/disconnect, and print out the player list in the command window (including scoreboard) at the end of each game.
• Use an [R] prefix for rcon commands and echo command output to server console as well as sending it to rcon client.
• Enabled logfiles (writes out console output and some command line errors only to files in logfiles_dedicatedserver). You can still override the logfile directory by specifying -logdir
• Small performance optimisations
• Dedicated server species ratios' commands check for unset values and report the default values instead of the invalid value (-1). The dedicated server was correctly setup in this case, but the command feedback text was inaccurate.
The patch should automatically be applied when the Steam client is run, or restarted if already running.