Oh I see. Well it's very obvious that all the live performances are live only in that they were recorded all at once with no breaks. Perhaps they were recorded several times and the best take chosen, but that, sadly is the legal definition of "live".
As long as the actual artiste is up on stage and the "live" track playing then it's O.K. That's how it is! Hollie couldn't keep up with the track because she felt the song she was singing unlike SuRobot