Comment 10 for bug 381599

Looking through the packages. It seems that the following is possible, however highly unlikely:
kwordpart.desktop and kwordpart.so are in different packages, so if the former gets installed before the latter, kbuildsycoca might, or might not, fail to add kwordpart to the database (because obviously the library is missing anyway). Judging from earlier encounters with sycoca weirdness this seems rather impossible because from what I know, kbuildsycoca4 will add the part no matter whether there is a library or not, only at actual application runtime it will become noticed and treated (we can see this for example in system settings when the case desktopfile-avail-lib-unavail applies).

Other than that I can hardly imagine anything that could cause this issue packaging wise. So, if someone could go check over at http://bugs.kde.org if KDE got a report for this (ultimately with reports from distributions other than Kubuntu/Ubuntu ;-)).