I do not see any way in JRiver to delete a tag from flac files in an album, so I tried this:
Remove album from JRiver.
Exit JRiver.
Use dbpoweramp to delete the tags - gone from the file.
Start up JRiver
Import
The Album gets re-imported but those tags are still in the database.
If I move the album to a different directory then import, it works. But I don't want to rename the directory.
For some reason, the DB record does not get deleted then when it gets "re-used" old values are still there.