Thread:Ironwestie/@comment-31829114-20170729045458/@comment-5754239-20170729051224

I've done some digging, mostly at Help:Sorting and Help:Sorting on Wikipedia, and most of the time there is a formatting issue.

As per Wikipedia:Help:Sorting, there are some formatting issues that we seem to have incurred:
 * Year should work, as long as there is no text before the year.
 * Year and month does not work (e.g. "2010 January")
 * Month and year does not work (e.g. "January 2010")

You may want to look at that page yourself for a list of date formats that will / will not work.