I updated to 4.1.2, and two pages on the site started throwing this error at the top of the page. Downgrading to 4.1.0 cleared it up 
Only major thing I had done after upgrading to 4.1.2 was disabling the Portfolio in the Theme Options area (thanks for that option, btw!)
It was a live site, so I didn’t want to leave this error visible… but I can create a staging site if you need it.
