User blog comment:DaNASCAT/Technical Update: April 6, 2016/@comment-1251315-20160406203451/@comment-1251315-20160407150241

@Cqm: I'm aware of the differences between them, however SMW is so buggy on Wikia that the data is never up-to-date (things like Concepts and BrowseData are basically broken pages that don't update any more).

A lot of people on Narutopedia probably don't even care about the annotated data and would probably just be fine with categories on pages (and using DPL to generate the list in a dropdown). Some sysops are also not interested in looking at SMW based pages and seeing the same name repeated about 25-30 times or queries not working, especially as they're never even looked at.

Anyway, I'm getting somewhat off-topic on this, I'll ask local sysops to investigate the problem, but I suspect it's probably SMW causing all the problems (as it has been for a while now on Wikia).