> That shouldn't happen. There shouldn't be any way to mess up the code so that it doesn't always say 'congratulations,' unless the code for winning the puzzle was weirdly complex when it came to winning. Additionally, it's a relatively recent game (2015), so it shouldn't have glitches like that where the devs weren't able to test everything extensively.
Of course, it's possible the devs didn't notice this (assuming it is possible), or that they did notice, tried to fix it, couldn't, and decided that it doesn't matter ("Let's make it an easter egg!" dev 1 says, all others agree)