It's always November, isn't it? I've once made a log collection system that had a map of month names to months (had to create it because Go date package didn't support that specific abbreviation for month names).

As you might've guessed, it lacked November, but no one noticed for 4+ months, and I've left the company since. It created a local meme #nolognovember and even got to the public (it was in Russia: https://pikabu.ru/story/no_log_november_10441606)