Using the search feature I saw that this issue has been reported before and was apparently fixed a while ago but I didn't want to necro-post on year + posts.  I've been playing with some friends via ICO these past few weeks and we're encountering de-sync issues where one or two of us will be seeing one state of the game while the other person(s) are basically playing against AI at some point during the game once the de-sync occurs.  Pretty obvious when playing vs. each other and we can rename the same planet, since it shows player owned for both opposing teams..  Is there something we can do to reduce/eliminate whatever is causing de-sync'ing (note, no one ever disconnects and typically lag isn't occurring / pings remain low.)?

Running Diplomacy, latest version.