He leaks them during Mario's spotlight

That day the race went on as it was supposed to. Still feeling a bit embarrassed about last night Peach doesn't perform as well, she places 3rd with Daisy in 2nd and Mario in 1st.

As the three stand on the winners podiums. The reporters ask the usual question when suddenly their phones chime. Checking it there are audible gasps in the crowd before the reporters turn on Mario. Peach is shocked as she hears the reporters accuse him of cheating on royalty and Peach even defends him. At least until they show her the pictures. Peach's heart breaks as she sees him give Pauline a mustache ride. As her heart falls her anger rises and her frustrations finally snap! She grabs the first place trophy, reels back and smashes Mario across the face with it knocking him out. After the hit Peach realizes too late that the reporters just caught that whole thing on film. Peach runs to the locker rooms to get away from them.

Daisy is left stunned. Yet again the plan doesn't go as expected but is still beneficial. Their plot doesn't have the chance to continue as Peach returns to the mushroom kingdom immediately. The scandal damages Mario's reputation but the outburst from Peach also hurt hers. But to Bowser this was just what he needed, with Peach feeling unloved by both Mario and even her people she is in the perfect mindset for the last stage of his plan.