peter I don‘t see this issue in version 3.7.2. If I duplicate a song and then delete one of the two the app will never ask you if you want to delete the audio file as it knows that another song is using it. It will only ask if there is no other song pointing to that file and when you then choose to keep the file it is of course reloaded when you refresh the song list. So if you see the dialog you can be sure that there is no other song using that file.
All i can say is what i am experiencing, and that is when you delete songs that are duplicates and then you refresh your database , these songs pop up again , i want them gone forever so i can refresh my database without all the old songs i have deleted.
Basically if you delete songs you then should never refresh your database as that will bring back all your deleted songs , this makes no sense , you cant seem to tidy up your song library , unless you never database sync again.
Which makes the database sync useless.
Songs that get deleted from song mode need to be removed from the database as well so you are in sync with what you are trying to do and that is clean up your song list, getting rid of duplicates that are similar , there needs to be a master area you can trust, and that should be SONG the database behind it should be exactly the same , no hidden undeleted files behind the sceenes.