Duplicate meta description tags are probably a result of a templated approach to page production. However, if meta tags are not customized, it’s better to have no meta tag at all than duplicates. I would recommend removing the description tag from the template altogether until custom tags can be developed, or, using a variable as well that pulls the page content up to a max of 160 characters.
Based on this feedback, I think we need to make 2 changes.
remove description metatag if a unique description was not set for the page.
Set a max limit of 160 characters for the description metatags