So it seems like chess notation is sometimes ambiguous? For instance the two different moves below are both denoted Qbc4 in chess dot com. It seems in this situation the starting file b is not enough too disambiguate since both queens start on file b. I would think here that you need further info like Qb4c4 vs Qb3c4.

/mantej | Cryptography Engineering at Cash App

Yeah seems very unlikely to happen in a normal game, but you can definitely reach a position like that from a normal starting position. So once you’ve played the ambiguous move it would not be possible to reproduce the game after that point. Maybe I’ll create a new game and see what happens if I save it.

That’s a good catch! It’s likely a niche enough scenario that it ~never occurs in games, but depending on how widespread this bug is, could cause some difficulty reproducing a game