- don’t change agents willy-nilly, particularly when you already converted to the new “Plex Movie” agent. Otherwise you might have to Plex dance at least the affected items.
Don’t switch back to the old “legacy” agents. - two instances of the same actor are a side effect of a recent bug fix. To solve it, do nothing than refresh metadata of the whole library
- make sure that “Prefer local meta data” is NOT ticked in the properties of your library
- checking your database for damage can’t hurt
