I played a number of 2v2 games over the weekend with a friend of mine and two AI players.
In every game where a human player was playing as a General Demigod, the game Desync'ed (not immediately, but long before the game was over). In every game where both human players were playing Assassin Demigods, everything worked fine and we were able to complete the game with no Desync problems. [Note: 2 Human Assassins and 2 AI Generals worked fine, but 1 Human Assassin, 1 Human General and 2 AI Assassins yielded a Desync].
Note: My friend's machine is borderline with regards to system specifications due to CPU (I don't know exactly what he has but it's not great). Therefore, sometimes we experience a bit of game slow-down when too many units are actively engaged in combat (which is fine and is to be expected with a borderline machine). However, this slow-down seems to be un-related to the Desync because it occured in both games with a Human General (where things eventually Desync'ed) and games with 2 Human Assassins (where the game finished fine).
Note: Unsurprisingly, both my friend and I are able to successfully complete solo games with 1 Human General and 3 AI players.
If there's any additional information that I can provide that would be helpful, please let me know.