There are many obvious factors that Rachel is not the one behind the ideas presented as her own. This is especially obvious to the crown prince who pays close attention to Marie and knows her to be the one that always has a solution to seemingly impossible situations
I think it's mostly due to the fact that he knows Rachel is "borrowing" Marie from him, which was sus. He's connecting the dots since he's aware that Marie is capable and he's finding holes in Rachels explanations of her "work".
That's true. Just what I thought to
I mean it is Marie behind it all but why is he so sure it's her? It's not like he gets the bts like us. Also, is he getting close to figuring out her real identity?