Google vs DuckDuckGo datapoint

Blogger is a google project, of course. I wanted to find a link to a quick review I'd done of a book, on blogger. Google should be able to keep track of it's siblings, right? The result on google was "Your search - "1177 b.c." site:idontknowbut.blogspot.com - did not match any documents."

DuckDuckGo pointed me to the post I wanted.

The google settings include SafeSearch ON (locked on by the browser, apparently). I can't think of anything terribly unsafe or offensive about the post, and IIRC D.D.G. used a safe search by default. The results were the same w/ chrome and firefox.