Running a custom map, using Tunngle (as we've had bad experiences with lag using ICO), two players and one AI. Game seemed to be in sync for the first 15 minutes or so then at some point after that, it went out of sync without any indication that we'd lost sync.
We only noticed it had happened when sending envoys to the other player controlled worlds. Had no problems running with the last beta build, only today's build, though that could be coincidence.