I highly doubt this will be touched mostly for the Fact it's a Thermos issue. Plain Bukkit in 1.7.10 works, but with Thermos modded Achievements sadly are not showing up. Not sure if there is a small chance or too bloating to maybe grab said info.

I also made a report to Crucible on this. It's a updated version of Thermos being semi active worked on:
CrucibleMC/Crucible#72

Thanks.

This isn't a DiscordSRV issue, but likely isn't fixable either because Achievement is a enum in Bukkit - thus meaning new values cannot be added