I have now noticed the same kind of problem but without having duplicate AC and now on the artist page itself (with the list of release groups):
In this artist where all the release groups are by the artist itself and without any artist credits, there used to be no Artist column at all.
But now there is.
It could be a regression from a migration of the artist page to the new GUI framework, which I forgot the name, REACT or something.
Every artist in my subscriptions seems to have the artist column on the overview page, even those without any aliases or ACs. I don’t remember how long it has been like that, because I don’t even remember a time when this column wasn’t there … Half a year ago I wasn’t yet a MB user