Issue with alternate char `a` on Firefox Linux

[xavhan]

Font Name (Geist Sans/Geist Mono):

• Geist Sans
• Geist Mono

Description of the Issue:
Some of my users have trouble with the display of one char: a

In font-weight=500 font-size=12px on firefox Linux, alternate a's are looking off.

font-feature-settings: "ss01" 1, "ss02" 0, "ss03" 1, "ss04" 1, "ss05" 0, "ss06" 1, "ss07" 0, "ss08" 1, "ss09" 0;

Steps to Reproduce:

Expected Behavior:
I expect the a to be rendered the same everywhere regardless of browser or OS.

Screenshots:

this is how it looks on firefox linux

this is how it looks everywhere else

Environment (please complete the following information):

• OS: Linux
• Software: Firefox
• Version of the Font: ^1.7.1