Those really really big numbers...I'm not convinced that's a normal exploit even. There was a very early version of the game where people could sell fish at any price using a trick...that has been fixed. But it would not explain those really insanely large numbers...to me that looks like a 'rolling over' of the score, as if perhaps the player managed to go into the negative with their earnings, and confused the game.
I'll look into it.
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Arthur
Lead Designer
Last Day of Work