Your coworker gave you a nice compliment. But also let you know there is no upward mobility if that is what you are looking for. That was super kind of them.

Your coworker is an instigator.

Your boss left or the colleague left? Who would leave if it were you? If it were you who had been promoted, then she would have left? or if the other person had been promoted, and if she was you, she would have left ?

Sounds like your coworker thought you should be promoted over the other senior person and it was a compliment.

You probably aren't missing anything. Some people just cause drama. Judge every person and situation for yourself.

I work in a small team. Our boss gives us a lot of autonomy to do our work. One of my colleagues is always telling me that I do a lot of things my boss should be doing. He recently announced he is leaving the company and the next senior member of our team will be leading the team in the interim (she is not assuming his role). The senior member was disappointed it was not a promotion. My colleague later says to me, I’m glad it wasn’t a promotion. I replied, why? She said, if she had been promoted, I’d leave if I were you.

If she had been promoted, it would not have bothered me in the least. What am I missing? I should add that my colleague was annoyed that the senior member did not give credit for work performed by me and my colleague. This kind of stuff doesn’t bother me unless it’s pretty egregious.