I think it's a bug disguised as a feature. I implemented a timer to check if you get stuck in an infinite loop, and if so, quit. I suppose a better way to do it would be to first check if you're still on the same input, or increase the maximum number of cycles. I'll fix it soon.
Just to make sure, you're not going beyond the final input before writing the final output? There's an error that clearly says "Too many cycles" or smth like that? (I don't remember anymore how exactly this game works...)
Anyhow thank you for still showing interest in this game! :)