https://musicbrainz.org/work/7f96b779-5e84-34fa-8054-144d24e85fe9 contains 2 of the same wikidata url's.
One contains http:// and one contains https:// so both url's are unique but point to the same entry.
When the entry was merged the code must have not detected the difference and allowed both to exist after this was merged instead of getting rid of the http version of the url.