Steps to reproduce:

1. Copy this:

<ref name="Example">Burci, Gian Luca; Vignes, Claude-Henri (2004-01-01). [https://books.google.com/books?id=Xou_nD9jJF0C ''World Health Organization'']. Kluwer Law International. ISBN 9789041122735. Pages 15–20.</ref>

2. Open a page in the visual editor and paste it in. (Might need to use Safari 9/Mac OS 10.10.5, because of T134228: Can't paste wikitext references.)

3. Wait for the wikitext to convert. See claim that the ref is defined elsewhere when you select the ref number:

4. Look at the ref name when it's saved, to see a "2" appended to it (screenshot is https://en.wikipedia.org/w/index.php?diff=718359262).