Nah, the game has it right. It's just one of those words - I'm normally good with spelling, but it's always looked wrong to me. It looks to me like it 'should' have another t, and maybe even only one n. It's like there's part of my psyche that is annoyed with the city for spelling itself 'wrong'.
I mean, it couldn't be my brain that is just wrong. That could never happen.