Here we have to add a style tag. The bug is that you can only pass the test if you add a slash to the end of the tag.
<link rel="stylesheet" type="text/css" href="styles.css" /> passes
<link rel="stylesheet" type="text/css" href="styles.css" > does not pass. To my knowledge the slash at the end of a self-closing tag is not a requirement. Also, I could pass the test before when I added the meta tag which is also self-closing and did not require me to add the slash at the end.
I know I’m a little bit behind but maybe this is helpful for others who are also struggling with this.