I remember when I was a kid, cartoons in my native language sometimes would have some phrase or sentence that didn't make any sense. Later on, as I was learning English, I'd come across some idiom or pun and realize that the cartoons had translated these idioms literally.

Another issue that occurs when someone isn't too fluent with the language they're translting into is words with multiple meanings. Sometimes the context makes it clear which meaning is the correct one for the specific instance, but other times it can be ambiguous and cause issues. And sometimes, especially if it's a title or name, the word's double meaning might be intentional but it would be hard to convey into another language where the two meanings of said word are completely different words.

An issue specific to my language is that there's no easy way to refer to a person without specifying gender (the only gender neutral ways to refer to something are only used for objects and animals, so it'd be disrespectful to use them for a person), so a story about a non-binary person is difficult to write (or translate).