Managing someone who doesn’t want to be managed by me (union)

Hello Managers.

I am in a rather unique situation where I have inherited a new team and the Director of that team does not want to report to me. I know this for a variety of reasons, including being aware that they asked for their old boss’s job (a higher title than their current) on a few occasions before being reorganized under my team.

My issue is that my standard management approach, one that has lead to numerous positive and collegial working relationships, isn’t working with this individual. They are extremely reticent in our weekly 1:1s, giving me one word answers for things, telling me to “go look” at their project management tool for an accounting of their tasks (they aren’t all there), I routinely don’t hear from this person outside of our 1:1s.

A few weeks ago, they sent material straight to my boss copying me, and when I reasonably asked them to be sure to send things to me to review first, they seemed extremely offended.

We’re unionized so I’m struggling to think of what to do. Frankly, I’m starting to dread this person, because it’s so much effort to get any information from them. All of my other reports and I have such a positive relationship that this is an anomalous situation to me.

I have been documenting everything and my boss is very aware of these challenges.