https://pastebin.com/dU4prBH1

Fixed by starting a new world that hasn't used Sound Filters in the past.

Just kidding, still persists even on new worlds.

It should be fixed in master, here's a build. But it's a pretty weird issue, could i have the full log ? i'd like to see if something bad happened at the init for it to not have a reference to the minecraft instance.

I'll paste it once it pops up again. Its pretty uncommon it seems. I've been on the latest build.

Could you upload a release of that build on GH so we could use it in our modpack via Mod Director?

It was a good time to make a release anyways so i went ahead and made one. You can find it here.