I am almost positive that I have updated openAL in the past and then reverted it because it caused random issues for people. Either it crashed or it didn't run or it was the sound mix up issue. I don't remember exactly because it was years ago, but I'm pretty sure we've been down this path before.
Ahh, now it's starting to make a lot more sense. I couldn't see it just being left on 1.0 unintentionally for this long, so I was wondering what might have kept you from updating it. I apologize for making it sound so much like a plain "fix-all" solution that can't be wrong, but that's more attributed to how I saw effectively zero issues with it most of the time. I think it's still reasonable to say that the option does exist and
does to fix these historic issues.
It seems to run for everybody so far, and I don't think sounds get mixed up until the audio driver is reloaded while the game is running, or many audio profiles are switched out (leaving to join another server). I hope everybody can somehow find a way to solve sounds getting mixed up, but letting people know that it does work, with fair warning, seems reasonable: it's perfectly fine for things like recording videos of Blockland where you wouldn't be hopping servers anyway (or similar cases).
I've made the warning about possible issues in the OP more noticeable for the time being.