[Alneyan]

Then I accept the trade. Then I work on production

Do you accept the trade as the very Last thing in your turn (a few seconds before ending your turn), or do something else after that? It is the only known explanation for the trade bug, and that part of your message worries me a bit. And what about Mark?

I am not sure if the trade bug strike when you accept the trade, when you propose it, or both. I have a hunch it happens at both times; the actual message may be sent fine, but the contents of the trade are lost in the process. At least, that is a theory based on no ground whatsoever, but...

If not, I don't have the slightest clue about what isn't working for you. The closest to hit was what happened in the NGC games, where one player couldn't accept any trade. I am not too sure if this problem had been solved or not; perhaps Ruatha has a better answer about this. But the NGC games are much bigger than our 2vs2 game, and sheer size may be a factor triggering the trade bug.