We've been playing a few multiplayer (4 player) games using the latest set of betas here is our experience so far regarding desyncs:
Played a 4 player game in 4.066 for about 4 hours without problems, saved the game to continue later.
We then all updated to 4.067 before our next session but could not get the game started. After loading up the save game and the other 3 players connected the game would start and 2 players would show as desynced in the stats page. A forced resync from the manage players page would send data to everyone but still get stuck saying 2 players were desynced.
We then decided to start a new game in 4.067 because we could not get our old savegame working. The new 4 player game in 4.067 played fine for 5 minutes and then we got a desync. I (the host) did a manual resync from the manage players page which fixed it and we continue to play for another couple of hours, then saved the game.
Not learning from our previous mistake, we again updated to 4.068 before our next session and could not get the savegame from 4.067 to start. Players would receive data and as soon as the game started some players would have desync next to their name in the stats page and also resyncing from the manage players page did not help.
So now we're about 5 hours into a new game started on 4.068 and decided we'll stay on this patch level until the game is finished
no desyncs yet!