Actually, “Día de los Muertos” due to their film of the same name.
In an attempt to secure domain for merchandise around the Pixar film, Disney tried to trademark the phrase. However, all they received was backlash on social media for trying to trademark the name of a famous (probably the most famous) Mexican tradition which is also the theme of the movie.
Disney later issued a statement suggesting that they had decided to change the title of the film, and would therefore no longer be pursuing efforts to trademark the term. The movie was finally released as Coco.