Probably nothing can be done about it except take scissors and cut the spots out. Once leaves are formed and mature there is nothing that can remove spots. I am hoping that you and others that are posting about similar conditions on peonies are aware of two things. Marks on leaves are permanent for this season and no treatment will remove them. That once it freezes the leaves for this year are dead. If you worry about diseases for next year remove the foliage. Growers have already started digging so removing all of the foliage will only cause a slight decline in the nutrients that the leaves provide sending nutrients back to the roots.

I see. Thank you. :)