See https://en.wikipedia.org/wiki/User_talk:LilHelpa#WP:CITEVAR
In this edit https://en.wikipedia.org/w/index.php?title=Art_of_Mesopotamia&diff=next&oldid=694823407 AWB changed the citation style by merging duplicate references in an article that had no merged references before. Although the article had a reference with a name, that reference was only used once.