There is an issue which I have noticed long time ago. On my profile it says Games abandoned: 9%. That would account for 300-350 games out of almost 3600. However, I don't remember leaving more than 1-2 games (when I was R5), I have always surrendered instead.
The problem with it is probably inclusion of single player games, e.g. when everybody leaves or when you test something in private. Is there a possibility to fix this? I am absolutely sure my percentage of abandoned games is <0.05%.
