In this case, that profile is a historically-significant ancestor. Additional profile managers are sometimes removed from those, so that the person who's actively managing it is the one who gets merge requests, trusted list requests, etc.
As long as people aren't being removed from trusted lists (and you weren't in this case), it doesn't really make a practical difference. You can still edit that profile, and changes to it still appear on your watchlist. And of course, it's still in your tree.
That being said, if someone is inappropriately removing people as managers or from the trusted list of a profile, let us know.
I hope that help!