Horrible Coop Multiplayer Bug -- Games become different as city becomes more complex

[copy paper]

I play co-op with a friend over the internet. We've been playing a huge city as the same company, and as we play the version of the game in my save has become very different from the one in my friend's game. We wind up with different balances, different costs, etc. If my friend buys something for an amount of money that would take more than the amount of money my game says we have, it tanks me far into the negative and I can't purchase anything until it fixes. Further, sometimes things that I have built do not show up in my friend's world.

It is as is the server is not doing any kind of authoritative checks and the in game math isn't adding up.

The only way we've found to fix it is to manually transfer the multiplayer save game over from my friend to my computer, and erasing the old one. Anything I've built that my friend didn't see goes away, the numbers are once again the same, and we go from there. However this only fixes it for a few hours max until the two games start to drift apart again.

Is anyone else seeing this in coop? Is there a fix?

Thank you,
Copy Paper

 

[kensternation]

Unfortunately we have been complaining about the lack of synching for co-operative play since day 1. Nothing has been done or even much said, about it. I do not think the problem will be resolved by CO or Paradox.

 

[eis_os]

I am allowed to ask what cpu / os both PCs use?

Guess: As CIM2 uses floating point numbers on several pieces, small calculating differences may result in game differences over time...

 

[Stagua]

I and my coop partners _never_ got desynchronized if I was host and only I was saving / my partner was host and only him was saving the game (hint or just randomly happening?).