Maybe they are avoiding J-line stealing the show? They are probably getting more attention by default, so they are maybe trying to showcase the other girls now.They had a press conference prior to the KCON show and for some reason I felt they didn't want the J-line girls to speak all that much. There was a moment that Momo started speaking and then she and Jihyo exchanged looks and it was like "oops.. I don't think I should be talking so much." Most of the talk was lead by Jihyo and there was a Japanese translator for her.
I'm going to assume because they are still in their Korean promotions mode, and they have not officially started their Japanese promotions yet.
I'm assuming that their Japanese debut will be all out on the three of them, though.