This is a development of the issue discussed here: All tracks on unrecognised albums named the same - Plex Media Server / Metadata & Adding Files - Plex Forum
These files are now (recently) all showing empty titles. Refresh metadata now works for them and finally picks up metadata from the files’ tags, rather than renaming them all as per the final track in the folder, but I’ll need to update them all individually as I’ve made too many individual changes throughout my library to ever trust “Update All Metadata”!
Also, and potentially connected (at least it’s how I noticed this), Library Mix is now disproportionately preferring these unknown albums…
Otto - any thoughts on this?