It's probably not hurting you especially if it's only a small percentage of a solid backlink portfolio.  But it's also not helping at all.

To be safe, we suggest disavowing the one you shared and any similar ones since Moz gave it a spam score of 69%.

Your login pages will not affect your website's rankings one bit. You don't need to worry about optimizing your two login pages at all and it's okay that they have duplicate titles and content.

As an example, look at Hubspot's login page here, https://app.hubspot.com/login. Their title tag is "Hubspot Login" which makes sense. They don't have a meta description tag. The page has no H1. It is a thin content page.

You're going to see similar results for almost any login page you look at. https://moz.com/login has similar "issues" as well.

Just ignore the tool's recommendations for this type of page.