When joining three mysql tables, one record appears duplicated

As you can see, the problem is that the genres appear repeated, although the number of times that is repeated is correct

Note: I already solved the problem, the group by was the one that was interfering

SELECT serie_db.nombre,rating,GROUP_CONCAT(genero.nombre) FROM serie_db left join serie_db_generos on serie_db_generos.serie_db_id = serie_db.id left join genero on serie_db_generos.genero_id = genero.id group by serie_db_generos.serie_db_id