I can see this happening in the eco turn, where things like ceding are visible to other players in the turn sequence after you, but is this also the case in the diplomacy phase? Let's deal strictly with the diplomacy phase first. The diplomacy phase already had a hidden data base that was carried from player to player, with the final results only revealed/executed during the first reinforcement turn. This then should over write the databases on the other players computers. I can't see how this would not work without some overwriting, and the over writing in this case is a good thing.
In theory, all we have done, is at the end of the land phase, allowed each individual player to do their diplomacy as if they were the first player in the diplomacy phase (If player =GB, then GB's computer thinks it is first, if player=France, then France's computer thinks it is first, etc.). However, when the file goes out, it saves itself in the appropriate position (2nd, third, etc.)**
It seems to be that no one else needs load any diplomacy phase file from any other player except the first player in the reinforcement phase (typically Spain). Since who is going first in the reinforcement phase is known in advance of the turn (from the skipping data base that comes from the player who went last in the land phase), it seems easy to be able to determine who should be ultimately be loading the diplomacy phases (i.e. who is going first in reinforcement). This player (typically Spain) loads the other players diplomacy phases as provided in the correct sequence, skips/plays the AI turn as required, and plays their own diplomacy in the correct sequence (even if this is not the last nation to go). Then at the start of reinforcement, sends out the resolved/executed diplomacy. Even if Spain is an AI and GB is the first human player, this should work, as GB would send out a Spanish AI reinforcement turn with the resolved reinforcement.
The resolved/executed diplomacy is loaded by the other players, and should over write their diplomacy, as I imagine it already does. There should be no need for any player except the last to load any other players diplomacy.
Obviously, it is not working this way, but is this how it is meant to go? I can see a problem, if at where I indicated ** above, the game is over writing the previous players database during the resolution phase (typically Spain's reinforcement turn), so that by the time it gets to resolution it has wiped all the previous players databases (i.e., player 2's dip turn is wiping player 1's dip turn, and player 3's is wiping player 2's etc, as they are loaded by the Spanish player). Is this where things are going wrong? Do we need the game is only over write part of the database when it loads another players turn instead of the whole data base?
Is this only happening for AI move? If so, can we do IGO-UGO for games with less than 7 players, and sim for 7 player games (which is 99% of the games).
We might need a bit more explanation to assist you on this.