This looks like pesticide residue to me from when the plant was at the growers. It could also be hard water residue. Neither is harmful to the plant.
I recommend getting a clean damp cloth and wiping the leaves down while being careful not to damage them. It should come off no matter what it is.
If the whitish patches return then it could be powdery mildew. It doesn't look fuzzy enough but a closeup picture would help.
Thanks for uploading another picture. It looks like residue to me. You can confirm that this is a recently purchased plant and that any new growth that has opened since you purchased it does not have the white residue.
Just clean it off and check to see if it returns.