One can set any of the volume sliders to 0% (not OFF but 0%) and sounds will still play.
To recreate, slowly move the Volume slider towards OFF. One may notice that the slider can sit in between volume OFF and 1%, showing 0%. Then just check the game volume and notice how it still plays sounds.
Note, this was first tested and screenshotted whilst playing modded version OptiFine HD U G9 pre17, but same behaviour occurs in official release 1.17
Thank you for your report!
We're tracking this issue in MC-55833, so this ticket is being resolved and linked as a duplicate.
I added 1.17 to the affected versions of that ticket.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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