Bug with Yoast.....
This maybe a bug with Yoast
SEO or it maybe Yoast... Not sure which. However latest dev build with yoast installed.
On the homepage you have the ad listings....
It says the cat name, poster and length of time ago it was posted inside each ad box. If you click on the poster name with yoast activated it does not navigate to the poster details. It just goes to the top of the home page.