I've seen complaints far back as June of this year, and Adobe replying they are "working on it". Just a little reminder to Adobe that "ducking" is still in your Esstential Sound panel, but it doesn't do anything, so you might as well remove it.
Any time you adjust something there, you have to regenerate ducking keyframes. It's not a very obvious 'thing' as the text doesn't jump out when it needs regenerating. So it escapes notice for many users. Sadly.