Hi Ben, thank you for answering me. My Stadia gamertag is Dambro93#6316.
I use a large database with almost all nations too. I removed recently 2 or 3 nations and then the problem occurs, I don't know if there is any link because for some days the game works well. Before this issue I was non able to overwrite the savings, any error message appeared, but when I loaded the game I had to play a match that I had already played. I solved this problem saving with a different file name. I don't know exactly when this problem occurred, maybe 1 month ago, but I'm not sure, however not at the beg