Apparently both the actors were supposed to perform live at the show organised by Ekta Kapoor. But due to work commitments, both wanted to perform at the same time.
However, eventually none of them could make it to the live event. In fact we hear that Saif pre-shot his act at 2 am the day before the event and the Khiladi shot his immediately after the event. As long as we can see the two on stage, it’s okay.