Pretty sure this is all that's wrong. Without the patch, the URLs are returned in the webservice with partner=musicbrainz already added to the URL, so when it gets compared to what's in the DB it sees it as changed. I manually tested editing a release with OZON.ru relationships and saw that it didn't generate any bad edits anymore. Also looked at what's rendered on the release page and saw the href for these still include partner=musicbrainz.
Pretty sure this is all that's wrong. Without the patch, the URLs are returned in the webservice with partner=musicbrainz already added to the URL, so when it gets compared to what's in the DB it sees it as changed. I manually tested editing a release with OZON.ru relationships and saw that it didn't generate any bad edits anymore. Also looked at what's rendered on the release page and saw the href for these still include partner=musicbrainz.