We've tested this a lot and it seems a performance issue of either the GPU, CPU or both. playing a small map with low resources will start fine in the beginning but at some point desync every 20turns, then every 5 turns then every 2nd turn. Loading game, rebooting computer solves the issue for 10 or 15 turns and it comes back to every 2nd turn. Copy paste the game to a more potent computer and the desync is gone. Can play all the way through. Now loading a middle sized map. Desync comes much sooner in the game. copy paste to more potent computer and desync is gone until final stages of game. Here the desync now also comes on the more potent machine. now we copy paste the file to an even more potent computer (Yes we have 20+ computers here on our network) And 1 computer is always the i7-8700k the other one is always starting from an E4200 going up to faster CPU. And suddenly can play the game through until the end. Now on large or huge maps need even 2 i7-8700k but eventually the desync comes again. Now we switch from windowed mode to full screen mode and we can continue the game. Now we go to giga map (from mod) and for 400-450 turns without desync but eventually the desync comes again dispite 2 monster computers + full screen. Now we lower all settings to a minimum (no leader head animation etc) et voila, we can continue the game much further without desync up to turn 950! But eventually, even here the desync every x-th turn comes back. Since I won't mod for civ6 as I've done for civ4 and I won't hunt and debug code to find this one, I'm very amazed that the developers haven't caught the reason for the desync yet. It's obvious some performance lag causing this. Maybe even some memory out of bounds/allocation/issue triggering a desync. It shouldn't take a good programmer more than a few days to hunt this one. Before they expand and add expansions, fix the damn multiplayer issue! If you sell a game with multi as a specific feature, it's like telling your customer:"yeah, this car got a roof so you won't get wet in the rain and can drive in winter" and than the roof has a hole in it and you're not fixing it. That's a no go! Imagine some car company doing that and telling their customers:"we won't fix what we promised would be a working feature!" I'm pretty sure such a company would face bankruptcy for customers running away. I'm always astonished how much Gamers accept from companies as bugs and not fixing them. I would be ashamed such a persistent and repeatable bug for 2 years and not fixing it.