The content shown in parenthesis after an artist name (in a fanart.tv search) is what musicbrainz refers to as the disambiguation comment. A disambiguation comment is used to help distinguish identically named artists. It's not part of the artist name, just a separate field that lets the user differentiate artists with identical names. You get similar results if you do a search on musicbrainz.org:
http://musicbrainz.org/search?query=Bas ... ype=artist
If you go to the
fanart page for Bastille (South London based band), you don't see the "(South London based band)", only Bastille.
I'm not exactly sure why, but the search result above lists Bastille (German vocalist for Coppelius) first. When auto scraping, XBMC will use the first result if it has a score of 100 (you can see the score in the musicbrainz search results). The German vocalist for Coppelius currently has no images on fanart.tv so XBMC won't scrape any images. You can refresh the artist information which will bring up a box for you to select the correct Bastille. In my version of XBMC, the search result box doesn't display the disambiguation comment for all the results for some reason, but we know it's not the first.
A way to solve this issue is to use a music tagger that tags the music with the musicbrainz id (MBID). XBMC will then use the MBID instead of doing an artist name search.
Musicbrainz Picard is a very good one that I use. And there is a list of more taggers that use the MBID here:
https://musicbrainz.org/doc/MusicBrainz_Taggers
The two OneRepublic artists is due to someone creating a duplicate entry on musicbrainz. The two artists have since been merged on musicbrainz but both artist entries were imported in to the fanart.tv database before the merge on musicbrainz. As far as I know we don't currently have a way to delete artists on fanart.tv. We have the same issue with movies that have been deleted from TMDb and TV shows that have been deleted from TVDb. If a user on fanart.tv sees duplicates and isn't sure which one to use, the best bet would be to check the source (musicbrainz, TMDb, or TVDb) and verify the correct Id — fanart.tv uses the same Id as the sources.