Probably because nco:nameAdditional is not queried (it's indexed properly).
same for nco:nickname
Git commit 4bf40ee2476b3ffd97a6a0b65383192fac2c24f5 by Christian Mollekopf. Committed on 06/03/2013 at 17:30. Pushed by cmollekopf into branch 'KDE/4.10'. Also query for middle name and nickname. FIXED-IN: 4.10.2 M +1 -1 libkdepim/addresseelineedit.cpp http://commits.kde.org/kdepim/4bf40ee2476b3ffd97a6a0b65383192fac2c24f5