MS Teams Auto Opens A Specific Chat

Folks, starting yesterday, for no apparent reason, every time I open MS Teams, it goes to a certain colleague's chat thread (his name can be Bob for this discussion). I have dozens of people in my list of chat contacts. In the past when I opened Teams, it would always go to my pinned private chat with myself. Now it goes to Bob's chat automatically, every time I open Teams. I'm not sure why this started happening yesterday. I don't like this behavior and would like to revert to its previous behavior. Does anyone have any thoughts?

I'm using Teams version 25163.3611.3774.6315, which the app says is the latest.