  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 $\mathcal{E}_n$.
