I am a department director. I have an assistant director who does the direct management of my department's team members, but I occasionally meet with the team members directly as well, usually as a way of staying in touch with their professional development and listening for feedback.
In a recent one-on-one meeting, a team member complained to me about his manager, the assistant director. He cited some things she does that bother him, some of which seemed outcome based and some of which seemed behavior based. The complaints caught me by surprise, especially since they sounded like they had been simmering for a while. I thought some of his feedback seemed legitimate and worth investigating, and some of it seemed overblown. In the meeting, I simply listened and asked a few questions - I did not offer any reactions, opinions, or suggestions myself.
How do I address this with my assistant director?