Sorry - but I can't understand what https://github.com/musicbrainz/picard/commit/d20a7c1 does and why you made the change. I am not sure that your proposed solution will work. If the existing file is id3v24 then we need to display and compare the details as-is which means that Original values need to be stored in metadata not ID3Metadata. However if you are worried about garbage collection, we can set "self.orig_metadata = metadata" and copy into self.metadata as shown.