It's slightly different in the novel. But I doubt it's a typo cause NoPainNoGay was written the same in Ch.56 if you go back & look at the leaderboard. If I had to guess, they probably changed his name cause it fits better then the one his Novel counterpart has.
Gosh darn, I LOVE the way this Manhwa focuses on the love between the MC and father. It's so sweet yet so sad at the same time