Existing artist initially not showing up during credit editing, but later they do - causing duplicates

I have lots of on German-language pop/rock music from smaller/“indie” labels and the quality of the predefined metadata is rather poor - in comparison to e.g. US bands where it is very usable even for many small labels.

So I have to edit credits a lot and very frequently this happens (same in 1.7 and 1.8):

  1. Add credit, search for Artist
  2. Artist not found, “create artist?” > Yes
  3. Finish editing, save
  4. Search for artist name, suddenly it does find an existing and correct artist of the name, now I have two!
  5. Merging the artists is possible most of the time but sometimes it just won’t let me, no idea why
  6. If I cannot merge, I have to go back to the album, remove the artist credits I created.
  7. Adding them again, and now it does show both the existing artist and the one I created, so I can choose the existing one.

Very annoying!

Sometimes, it is already the predefined metadata from several imported albums that automatically created several versions of the same artist. One of those typically has better data, so I would like to merge them all into this one. Again, this is possible most of the time but now always, and I have to go any manually exchange the artist on an album just like described above.