Poincar\'e/Koszul Duality for General Operads

We record a result concerning the Koszul dual of the arity filtration on an operad. This result is then used to give conditions under which, for a general operad, the Poincar'e/Koszul duality arrow of Ayala-Francis is an equivalence. We discuss how the Poincar'e/Koszul duality arrow for the little $n$-disks operad ${\mathcal{E}}_n$ relates to their work when combined with the self-Koszul duality of ${\mathcal{E}}_n$.