Firefox Underline Bug

[mrwweb]

Describe the bug
Screenshot from Ollie Demo site:

To Reproduce

1. Hover over a link in Firefox

Expected behavior

Should look like Chrome:

Additional context

I had assumed this was a bug on my site until I saw this also on the official demo site. I have not dug in to try to figure out what's causing the issue.

[mrwweb]

I'm struggling to work up a reduced text case, but the underline width goes back to normal when removing font: inherit from the styles.