Hi!
I have since just gone through the few dozen local albums I have and redid all the relevant metadata (mostly just set favorites).
This is a solution I haven’t tried yet, so I’m optimistic it would work. But since I now have a current version running, with newer changes to my library, I won’t redo an old backup. But when I next restore a backup (will happen sooner or hopefully later), I’ll be sure to try this if I encounter the problem again.
Thanks for the help!