There seems to be some sort of audio lag issue. Some audios will work others won't. I noticed it first in realismcraft so I thought it was just a weird glitch with that stuff. But no it's a all of minecraft issue. It's definitely not as bad in a normal world but it definitely exists. Like I can hear my foot steps I can hear mobs I can hear weather but at the same time can't hear eating attacking fall damage breaking blocks. But then it'll eventually switch? Then i can't hear walking or weather or mobs but then I can hear eating attacking and breaking blocks? It doesn't make sense but it's happening.