Permalinks no longer respect WP settings

I use the day and name option for my permalinks setting (http://gonzoecon.com/2016/12/06/sample-post/). Sometime in the last few days the post title has stopped being included in the url. Instead there is a five-digit number. I'm running v.3.6 of the theme and just updated to WP 4.7. (The problem started with 4.6.x, whatever the previous version was.) I realize this may not be a theme-related problem. I plan to post the same question on Wordpress.org. Thanks for any help. Best, Tony Lima