I have been using the Site content builder for most of my content and for a while it has been a great help with my content writing. But in the last few months it has been too critical with it's analysis. I put up a post recently and despite me doing multiple changes to my content the checker gave the message that my content is not 100% unique. I did some asking around on the WA community questions and i got the reply that the heading may be the culprit, it not some of the paragraphs.

I came to the conclusion that where you put your keyword in the heading and then again somewhere in the first paragraph, could the checker interpret this as identical content , thus the not unique message.?