Some ligatures aren't working (Fira Code)

[idmyn]

I haven't thoroughly tested all the ligatures to determine a pattern, but the screenshot below shows that although the inequality sign is working, the html comment symbol is not. The ligatures appear properly in other syntax themes, so it's not a problem with my font/atom install.

I assume it is somehow linked to this issue, but I'm not sure how I'd go about fixing it.