Extremely inconsistent volume despite mixer staying at the same level.

So my earbud (Moondrop Chu2) has some weird behavior where sometimes the volume is insanely loud and I can only tolerate it at like 20 on the mixer. But sometimes it becomes a lot quieter and I have to dial the mixer to 100 to make the sound reach audible level.

I have tried disabling Windows' automatically reduce volume of sound when it detects communication activity. This has been a problem for a while and honestly I'm stumped.

Anyone got any idea?