'next-head'  class being added to all the items in the the <HEAD>

I am using HEAD to populate the tags in the HTML document. Every tag though is being populated with a class added to it 'next-head'. Google SEO isn't liking it. How can i remove it?

<img width="777" alt="screen shot 2017-12-23 at 9 31 59 pm" src="https://user-images.githubusercontent.com/173148/34320922-30b3adfa-e829-11e7-8a88-da86d7c83712.png">
