Yesterday evening I've decided to play against Stockfish level 5 in Correspondence chess (2 days). Today I found my game lost by resigning. But I didn't push the resigning button!
Very strange indeed. And there's absolutely no possibility that somebody else used your computer in the meantime, while you were away, and resigned the game as a ... joke?
This is normal, if you play against SF somehow if you take longer than a day or so it resigns for you. No idea why, somewhat annoying since it's impossible to play CC games like that.