The disconnections were there before, but they've improved the disconnect detection so it dumps you instead of letting you continue playing and thinking you're on the server when you're really not and none of your progress is saving.

The way the server connections work is your local client runs the local part of the world you're in. Before the update there were lots of complaints from people who lost hours of progress and some people noticed that even though the game seemed to be running fine on their end the network information on the F2 screen was indicating they weren't connected to the server.

They still have a lot of work to do on the networking side of things to handle things better. The way they're doing things is really different from most games and it has some advantages like giving you much better game performance over a bad connection, but it makes syncing things up much more difficult when there are any problems between the client and server or with other nearby players.