iTunes Overwriting Files Instead of Making Duplicates

[Spectrum1013]

As the title says, for as long as I can remember, if you added the same files to your library twice (and use the options to copy files to library & keep library organized) iTunes would show you having doubles of every track on that record in your library, and in Finder, you would see doubles as well.

For some reason, and for a while now, I have not been seeing that behavior. And it's a PITA.

It's not limited solely to adding new files to the library, but say I have two copies of the same album and don't know it because the tags are slightly different. One album the way I'd like it tagged, and the other, I won't realize is a duplicate until I edit the tags and they match up with the other copy I have.

The end result of that would be, iTunes shows me having two copies of each track, but in Finder I'll see that for some reason by editing the tags, iTunes has chosen to overwrite the files when the tags match up.

And the most annoying aspect is, when I go to delete the duplicates from iTunes, and have it move files to the trash, it deletes my only copy of those songs.

I'm on what I believe to be current,
iTunes 12.9.0.164 & Mojave.

I've looked around and haven't found any help via google, so hope someone here has run into this...

Thanks