My issue was both before and after the update as well.

I have a similar problem, it can be circumvented by having a server admin boot you, and then reconnecting immediately to the same server. Unsure what causes it. I'm on Windows 7 x64. Additionally, it does the same thing for me in ARMA 2 Steam, with or without mods.

I will post more technical information later.

Edit: I too can be manually slotted by an admin on that first connection, however when they do so, often the game crashes or I disconnect after that.