The localized title for Mexico is "Último turno" which, I suppose by the MX in the language name, is the one that has priority over other titles when choosing one.
Even if you consider "En La Mira" as the one correct is wrongly spelled, it should be "En la mira", Spanish doesn't use the English title case.

Sources: https://www.imdb.com/title/tt1855199/releaseinfo#akas
https://www.blu-ray.com/movies/End-of-Watch-Blu-ray/91343/
https://es.wikipedia.org/wiki/End_of_Watch

By Wikipedia: "...titulada En la mira en Argentina, Último turno en México y Sin tregua en España...". 'En la mira' is the localized title for Argentina.