how to shorten link underlines?

For some reason, the links displayed by Post Grid have underlines that are significantly wider/larger than the actual link text. You can see an example at https://tampenteri.fi/ where you can see the orange link underline of “lue lis??” (read more) being significantly wider than the text itself.

The same problem also happens if I change the layout to show “title with link” instead of just “title” at the top. How do I change the underline size to make it fit along with the linked words?

WordPress 4.5.2
Post Grid 2.0.7

https://www.ads-software.com/plugins/post-grid/