After some more testing its continuing to occur, even in the "browse LAN games" menu. I'm not sure what part of a local game requires connection to a matchmaking server but this is leading me to believe it is not related to that.

Upon pressing "Browse public games" button in the multiplayer menu an error appears: "Notice - Select failed: invalid argument" and the server list does not load. Attempts to join through the Steam menu also result in "failed to establish communication to the server" me...

When trying to join a multiplayer server hosted by someone else on their PC, the game tried connecting and then claimed "could not establish network communication with server". This only occurs on non-steam version when attempting to join servers hosted by players, and not on standalone se...