Problem with snippet editor looking wierd

Hello. I recently updated Yoast SEO and the new snippet editor looks really strange. The text in the editor gets formated in a really strange way, do anyone here have a suggestion on a solution for this? Maybe it’s my theme causing it but it shouldn’t make any difference in the backend.

http://postimg.org/image/bg9vz3i6h/

https://ww.wp.xz.cn/plugins/wordpress-seo/