The keyword density is 0% – SEO by Yoast

Thank for awesome plugin.
I used this plugin long time and it’s very important with me. But some days ago, when I posting new post, I figured out that Page Analysis always say: The keyword density is 0%, which is a bit low, the keyword was found 0 times. Although, in the post included focus keyword. I’m waiting for your reply.

Thank you again.