Ok.
I searched within Plex for “Claude Monnet Presents Monica Nogueira” and it came up with a number of variously random tracks scattered throughout the library.
I then went and pulled each and every one of those tracks out of the Library’s directory structure and did the Plex Dance.
I then re-added the single Various Artists album I had tried earlier and it is now showing up as “Various Artists”. Whew.
At this stage, it seems clear that the mess is to be found within these few tracks that Plex tagged as “Claude Monnet Presents Monica Nogueira”.
At least, I am finally seeing a light at the end of the tunnel here.
