Maric as well
Apparently Korean is a genderless language and it depends on the rest of the words in a sentence, type of speech and notifications to tell if someone is talking about a man or a woman. I'm guessing some of these translations are done by bots and the teams putting them together aren't checking the translation Against the story or they don't really understand English and are assuming that it's correct (especially if they're translating into lots of different languages)
Unlike with terms for older siblings (which are based on the speaker's gender and the gender of their older sibling), there's just one term for younger siblings: dongsaeng (동생), so the gender has to inferred based on context.
I agree with the idea that the currently posted chapters are probably a machine translations, perhaps with some proofreading to check that it's intelligible, but little to no proofreading for correctness in the context of the story.
The younger sibling of the maid is clearly a girl. What's with the "younger brother" or "him"??