Triple Threat was made with Western fans of Asian martial arts films in mind who want to see all of their favorite actors sharing screentime.
When you take three very talented and popular martial arts actors from different Asian backgrounds who speak their own languages, and put them in a movie where they're supposed to communicate with each other in English, it ruins the character chemistry because their personalities are lost in translation.
There is also the paper-thin plot that goes nowhere and leaves questions unanswered, and the choreography that isn't supervised by any of the main leads who are known to skillfully and energetically choreograph their own fight scenes.