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4 player chess bots
Its probably because then the bot will just abort after that. The bots have been coded so that if there are just bots remaining in the game, then all of the bots immediately resign. If the game starts with 4 bots then game is aborted immediately. So you can't have 4 bots playin gin 1 game.
I was having stress why I always have to be in the game when I want all 4 players to be bots. I can't even do that.