Lending credence to the idea of a "skin tone" filter is a particular news article from a while ago. As related on Gizmodo, British police officers tried to create a bot to search for porn but it kept sending back pictures of sand dunes. Presumably the skin tone filter of that bot did as bots do, and acted absolutely, without context or nuance. The story has become known as "Send dunes" (send nudes, send dunes, sand dunes, get it? har har har.)
Now, this particular news story with its accompanying photo was posted on Tumblr...
And it got flagged.