In my test SP2013 farm, on a page with OOTB search result webpart, I key in follow query string in browser:
It seems recognized. However, as you can see in the picture refinement panel, the date format is weird. This "NewsArticleDate" property is storing Date only. The time should be 00:00:00. It makes the search input not matching the results returned.
If I input something like NewsArticleDate:2013/06/14 it will return the items with 2013/06/13T16:00:00Z which is not expected result.
What can I do to fix it?