Current stable versions of ncmpcpp with taglib duplicate existing tags when writing changes to files in the tag editor.
This has been reported upstream in https://github.com/arybczak/ncmpcpp/issues/371 and fixed with https://github.com/arybczak/ncmpcpp/pull/373
Since a new release containing this fix is not yet forthcoming, the ebuilds should be updated with a patch.
Steps to Reproduce:
1. Build ncmpcpp with taglib
2. Open a music file in the in-built editor
3. Make some changes such that tags will be re-written to the files
4. Save changes
Tags are duplicated in the music file
Tags are not duplicated, and changes are saved normally