with Peonies it is often advised to cut off the yellowing foliage and not compost it as it has quite a lot of fungus on it

on the other hand, older cultivars are often long-term survivors of given-up gardens, alng with Irises and sone others, where no one prunes off old foliage,

so I guess it does help to cut off the diseased foliage but most will pull trhough without any help

and yes, it is typicall for fall

I agree that it is nothing to be concerned about at this time of year. I would cut off all the foliage, tough, because it looks ugly